Tiny Fix in Docs for SliverFixedExtentList & SliverVariedExtentList (#154557)

Tiny Fix in Docs for `SliverFixedExtentList` & `SliverVariedExtentList`

Fixes #154554

Author: piedcipher

packages/flutter/lib/src/widgets/sliver.dart

@@ -422,7 +422,7 @@ class SliverFixedExtentList extends SliverMultiBoxAdaptorWidget {
   /// This constructor is appropriate for sliver lists with a large (or
   /// infinite) number of children whose extent is already determined.
   ///
-  /// Providing a non-null `itemCount` improves the ability of the [SliverGrid]
+  /// Providing a non-null `itemCount` improves the ability of the [SliverFixedExtentList]
   /// to estimate the maximum scroll extent.
   ///
   /// `itemBuilder` will be called only with indices greater than or equal to
@@ -582,7 +582,7 @@ class SliverVariedExtentList extends SliverMultiBoxAdaptorWidget {
   /// This constructor is appropriate for sliver lists with a large (or
   /// infinite) number of children whose extent is already determined.
   ///
-  /// Providing a non-null `itemCount` improves the ability of the [SliverGrid]
+  /// Providing a non-null `itemCount` improves the ability of the [SliverVariedExtentList]
   /// to estimate the maximum scroll extent.
   SliverVariedExtentList.builder({
     super.key,