Strip whitespace when injecting D209 newline (#1967)

Closes #1963.

src/rules/pydocstyle/rules.rs

@@ -528,12 +528,25 @@ pub fn newline_after_last_paragraph(checker: &mut Checker, docstring: &Docstring
                     );
                     if checker.patch(diagnostic.kind.code()) {
                         // Insert a newline just before the end-quote(s).
+                        let num_trailing_quotes = "'''".len();
+                        let num_trailing_spaces = last_line
+                            .chars()
+                            .rev()
+                            .skip(num_trailing_quotes)
+                            .take_while(|c| c.is_whitespace())
+                            .count();
                         let content = format!("\n{}", whitespace::clean(docstring.indentation));
-                        diagnostic.amend(Fix::insertion(
+                        diagnostic.amend(Fix::replacement(
                             content,
                             Location::new(
                                 docstring.expr.end_location.unwrap().row(),
-                                docstring.expr.end_location.unwrap().column() - "\"\"\"".len(),
+                                docstring.expr.end_location.unwrap().column()
+                                    - num_trailing_spaces
+                                    - num_trailing_quotes,
+                            ),
+                            Location::new(
+                                docstring.expr.end_location.unwrap().row(),
+                                docstring.expr.end_location.unwrap().column() - num_trailing_quotes,
                             ),
                         ));
                     }

src/rules/pydocstyle/snapshots/ruff__rules__pydocstyle__tests__D209_D.py.snap

@@ -19,4 +19,21 @@ expression: diagnostics
       row: 283
       column: 16
   parent: ~
+- kind:
+    NewLineAfterLastParagraph: ~
+  location:
+    row: 588
+    column: 4
+  end_location:
+    row: 590
+    column: 21
+  fix:
+    content: "\n    "
+    location:
+      row: 590
+      column: 16
+    end_location:
+      row: 590
+      column: 18
+  parent: ~
 

src/rules/pydocstyle/snapshots/ruff__rules__pydocstyle__tests__D213_D.py.snap

@@ -192,4 +192,14 @@ expression: diagnostics
     column: 7
   fix: ~
   parent: ~
+- kind:
+    MultiLineSummarySecondLine: ~
+  location:
+    row: 588
+    column: 4
+  end_location:
+    row: 590
+    column: 21
+  fix: ~
+  parent: ~