Improve API docs (#65394)

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

@@ -107,10 +107,10 @@ abstract class SliverGridLayout {
   /// const constructors so that they can be used in const expressions.
   const SliverGridLayout();
 
-  /// The minimum child index that is visible at (or after) this scroll offset.
+  /// The minimum child index that intersects with (or is after) this scroll offset.
   int getMinChildIndexForScrollOffset(double scrollOffset);
 
-  /// The maximum child index that is visible at (or before) this scroll offset.
+  /// The maximum child index that intersects with (or is before) this scroll offset.
   int getMaxChildIndexForScrollOffset(double scrollOffset);
 
   /// The size and position of the child with the given index.