Insert newline between docstring and following own line comment (#8216)

**Summary** Previously, own line comment following after a docstring
followed by newline(s) before the first content statement were treated
as trailing on the docstring and we didn't insert a newline after the
docstring as black would.

Before:
```python
class ModuleBrowser:
    """Browse module classes and functions in IDLE."""
    # This class is also the base class for pathbrowser.PathBrowser.

    def __init__(self, master, path, *, _htest=False, _utest=False):
        pass
```
After:
```python
class ModuleBrowser:
    """Browse module classes and functions in IDLE."""

    # This class is also the base class for pathbrowser.PathBrowser.

    def __init__(self, master, path, *, _htest=False, _utest=False):
        pass
```

I'm not entirely happy about hijacking
`handle_own_line_comment_between_statements`, but i don't know a better
spot to put it.

Fixes #7948

**Test Plan** Fixtures

crates/ruff_python_formatter/resources/test/fixtures/ruff/docstring.py

@@ -97,6 +97,45 @@ class ByteDocstring:
     b"""   has leading whitespace"""
     first_statement = 1
 
+class CommentAfterDocstring1:
+    """Browse module classes and functions in IDLE."""
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring2:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring3:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring4:
+    """Browse module classes and functions in IDLE."""
+
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring5:
+    """Browse module classes and functions in IDLE."""
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
 	def tabbed_indent(self):
 		"""check for correct tabbed formatting

crates/ruff_python_formatter/src/comments/placement.rs

@@ -1,8 +1,9 @@
 use std::cmp::Ordering;
 
 use ruff_python_ast::whitespace::indentation;
-use ruff_python_ast::AnyNodeRef;
-use ruff_python_ast::{self as ast, Comprehension, Expr, MatchCase, ModModule, Parameters};
+use ruff_python_ast::{
+    self as ast, AnyNodeRef, Comprehension, Expr, MatchCase, ModModule, Parameters,
+};
 use ruff_python_trivia::{
     find_only_token_in_range, indentation_at_offset, BackwardsTokenizer, CommentRanges,
     SimpleToken, SimpleTokenKind, SimpleTokenizer,
@@ -544,6 +545,10 @@ fn handle_own_line_comment_between_statements<'a>(
         return CommentPlacement::Default(comment);
     }
 
+    if comment.line_position().is_end_of_line() {
+        return CommentPlacement::Default(comment);
+    }
+
     // If the comment is directly attached to the following statement; make it a leading
     // comment:
     // ```python

crates/ruff_python_formatter/src/statement/suite.rs

@@ -584,9 +584,30 @@ impl Format<PyFormatContext<'_>> for DocstringStmt<'_> {
                     string_literal
                         .format()
                         .with_options(StringLayout::DocString),
-                    trailing_comments(node_comments.trailing),
                 ]
-            )
+            )?;
+
+            // Comments after docstrings need a newline between the docstring and the comment.
+            // (https://github.com/astral-sh/ruff/issues/7948)
+            // ```python
+            // class ModuleBrowser:
+            //     """Browse module classes and functions in IDLE."""
+            //     # ^ Insert a newline above here
+            //
+            //     def __init__(self, master, path, *, _htest=False, _utest=False):
+            //         pass
+            // ```
+            if let Some(own_line) = node_comments
+                .trailing
+                .iter()
+                .find(|comment| comment.line_position().is_own_line())
+            {
+                if lines_before(own_line.start(), f.context().source()) < 2 {
+                    empty_line().fmt(f)?;
+                }
+            }
+
+            trailing_comments(node_comments.trailing).fmt(f)
         }
     }
 }

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__fmtonoff.py.snap

@@ -225,8 +225,11 @@ d={'a':1,
          # fmt: on
          goes + here,
          andhere,
-@@ -122,8 +123,10 @@
+@@ -120,10 +121,13 @@
+ 
+     The comments between will be formatted. This is a known limitation.
      """
++
      # fmt: off
  
 -    # hey, that won't work
@@ -237,7 +240,7 @@ d={'a':1,
      # fmt: on
      pass
  
-@@ -138,7 +141,7 @@
+@@ -138,7 +142,7 @@
      now . considers . multiple . fmt . directives . within . one . prefix
      # fmt: on
      # fmt: off
@@ -246,7 +249,7 @@ d={'a':1,
      # fmt: on
  
  
-@@ -178,14 +181,18 @@
+@@ -178,14 +182,18 @@
          $
          """,
          # fmt: off
@@ -395,6 +398,7 @@ def off_and_on_without_data():
 
     The comments between will be formatted. This is a known limitation.
     """
+
     # fmt: off
 
 

crates/ruff_python_formatter/tests/snapshots/format@docstring.py.snap

@@ -103,6 +103,45 @@ class ByteDocstring:
     b"""   has leading whitespace"""
     first_statement = 1
 
+class CommentAfterDocstring1:
+    """Browse module classes and functions in IDLE."""
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring2:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring3:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring4:
+    """Browse module classes and functions in IDLE."""
+
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring5:
+    """Browse module classes and functions in IDLE."""
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
 	def tabbed_indent(self):
 		"""check for correct tabbed formatting
@@ -222,6 +261,46 @@ class ByteDocstring:
     first_statement = 1
 
 
+class CommentAfterDocstring1:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring2:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring3:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring4:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+    def __init__(self):
+        pass
+
+
+class CommentAfterDocstring5:
+    """Browse module classes and functions in IDLE."""
+
+    # This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
     def tabbed_indent(self):
         """check for correct tabbed formatting
@@ -341,6 +420,46 @@ class ByteDocstring:
   first_statement = 1
 
 
+class CommentAfterDocstring1:
+  """Browse module classes and functions in IDLE."""
+
+  # This class is also the base class for pathbrowser.PathBrowser.
+
+  def __init__(self):
+    pass
+
+
+class CommentAfterDocstring2:
+  """Browse module classes and functions in IDLE."""
+
+  # This class is also the base class for pathbrowser.PathBrowser.
+
+  def __init__(self):
+    pass
+
+
+class CommentAfterDocstring3:
+  """Browse module classes and functions in IDLE."""
+
+  # This class is also the base class for pathbrowser.PathBrowser.
+  def __init__(self):
+    pass
+
+
+class CommentAfterDocstring4:
+  """Browse module classes and functions in IDLE."""
+
+  # This class is also the base class for pathbrowser.PathBrowser.
+  def __init__(self):
+    pass
+
+
+class CommentAfterDocstring5:
+  """Browse module classes and functions in IDLE."""
+
+  # This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
   def tabbed_indent(self):
     """check for correct tabbed formatting
@@ -460,6 +579,46 @@ class ByteDocstring:
 	first_statement = 1
 
 
+class CommentAfterDocstring1:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring2:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring3:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring4:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring5:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
 	def tabbed_indent(self):
 		"""check for correct tabbed formatting
@@ -579,6 +738,46 @@ class ByteDocstring:
 	first_statement = 1
 
 
+class CommentAfterDocstring1:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring2:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring3:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring4:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+	def __init__(self):
+		pass
+
+
+class CommentAfterDocstring5:
+	"""Browse module classes and functions in IDLE."""
+
+	# This class is also the base class for pathbrowser.PathBrowser.
+
+
 class TabbedIndent:
 	def tabbed_indent(self):
 		"""check for correct tabbed formatting