fix edge case with PIE804 (#7922)

## Summary

`foo(**{})` was an overlooked edge case for `PIE804` which introduced a
crash within the Fix, introduced in #7884.

I've made it so that `foo(**{})` turns into `foo()` when applied with
`--fix`, but is that desired/expected? 🤔 Should we just ignore instead?

## Test Plan

`cargo test`

crates/ruff_linter/resources/test/fixtures/flake8_pie/PIE804.py

@@ -8,6 +8,8 @@ Foo.objects.create(**{"_id": some_id})  # PIE804
 
 Foo.objects.create(**{**bar})  # PIE804
 
+foo(**{})
+
 
 foo(**{**data, "foo": "buzz"})
 foo(**buzz)

crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_dict_kwargs.rs

@@ -88,16 +88,20 @@ pub(crate) fn unnecessary_dict_kwargs(checker: &mut Checker, expr: &Expr, kwargs
 
         let mut diagnostic = Diagnostic::new(UnnecessaryDictKwargs, expr.range());
 
-        diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
-            kwargs
-                .iter()
-                .zip(values.iter())
-                .map(|(kwarg, value)| {
-                    format!("{}={}", kwarg.value, checker.locator().slice(value.range()))
-                })
-                .join(", "),
-            kw.range(),
-        )));
+        if values.is_empty() {
+            diagnostic.set_fix(Fix::safe_edit(Edit::deletion(kw.start(), kw.end())));
+        } else {
+            diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                kwargs
+                    .iter()
+                    .zip(values.iter())
+                    .map(|(kwarg, value)| {
+                        format!("{}={}", kwarg.value, checker.locator().slice(value.range()))
+                    })
+                    .join(", "),
+                kw.range(),
+            )));
+        }
 
         checker.diagnostics.push(diagnostic);
     }

crates/ruff_linter/src/rules/flake8_pie/snapshots/ruff_linter__rules__flake8_pie__tests__PIE804_PIE804.py.snap

@@ -80,13 +80,15 @@ PIE804.py:7:1: PIE804 [*] Unnecessary `dict` kwargs
 10 10 | 
 
 PIE804.py:9:1: PIE804 [*] Unnecessary `dict` kwargs
-  |
-7 | Foo.objects.create(**{"_id": some_id})  # PIE804
-8 | 
-9 | Foo.objects.create(**{**bar})  # PIE804
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PIE804
-  |
-  = help: Remove unnecessary kwargs
+   |
+ 7 | Foo.objects.create(**{"_id": some_id})  # PIE804
+ 8 | 
+ 9 | Foo.objects.create(**{**bar})  # PIE804
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PIE804
+10 | 
+11 | foo(**{})
+   |
+   = help: Remove unnecessary kwargs
 
 ℹ Fix
 6  6  | 
@@ -95,7 +97,26 @@ PIE804.py:9:1: PIE804 [*] Unnecessary `dict` kwargs
 9     |-Foo.objects.create(**{**bar})  # PIE804
    9  |+Foo.objects.create(**bar)  # PIE804
 10 10 | 
-11 11 | 
-12 12 | foo(**{**data, "foo": "buzz"})
+11 11 | foo(**{})
+12 12 | 
+
+PIE804.py:11:1: PIE804 [*] Unnecessary `dict` kwargs
+   |
+ 9 | Foo.objects.create(**{**bar})  # PIE804
+10 | 
+11 | foo(**{})
+   | ^^^^^^^^^ PIE804
+   |
+   = help: Remove unnecessary kwargs
+
+ℹ Fix
+8  8  | 
+9  9  | Foo.objects.create(**{**bar})  # PIE804
+10 10 | 
+11    |-foo(**{})
+   11 |+foo()
+12 12 | 
+13 13 | 
+14 14 | foo(**{**data, "foo": "buzz"})