De-dupe docs (#101934)

Author: Piinks

packages/flutter/lib/src/rendering/debug_overflow_indicator.dart

@@ -85,8 +85,8 @@ class _OverflowRegionData {
 ///
 /// See also:
 ///
-///  * [RenderConstraintsTransformBox], [RenderConstraintsTransformBox], and
-///    [RenderFlex] for examples of classes that use this indicator mixin.
+///  * [RenderConstraintsTransformBox] and [RenderFlex] for examples of classes
+///    that use this indicator mixin.
 mixin DebugOverflowIndicatorMixin on RenderObject {
   static const Color _black = Color(0xBF000000);
   static const Color _yellow = Color(0xBFFFFF00);