Docs 'that that' fix (#50236)

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

@@ -3409,7 +3409,7 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   Element _retakeInactiveElement(GlobalKey key, Widget newWidget) {
     // The "inactivity" of the element being retaken here may be forward-looking: if
     // we are taking an element with a GlobalKey from an element that currently has
-    // it as a child, then we know that that element will soon no longer have that
+    // it as a child, then we know that element will soon no longer have that
     // element as a child. The only way that assumption could be false is if the
     // global key is being duplicated, and we'll try to track that using the
     // _debugTrackElementThatWillNeedToBeRebuiltDueToGlobalKeyShenanigans call below.