72344 Add BuildContext parameter to TextEditingController.buildTextSpan (cla: yes, f: material design, framework, waiting for tree to go green)

72382 [flutter_releases] Flutter 1.25.0-8.1.pre framework cherrypicks (cla: yes, engine, framework)

72384 Fix cupertino icons mapping which was misaligned by 1 (cla: yes, f: cupertino, framework, team)

72389 Nnbd docs updates for various widgets (cla: yes, framework, waiting for tree to go green)

72392 Migrate more doc samples (cla: yes, framework)

72395 Remove deprecated [PointerEnterEvent, PointerExitEvent].fromHoverEvent (cla: yes, framework, severe: API break, waiting for tree to go green)