Change ScrollView to inherit from ScrollableContainer rather than Widget

See #2332

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Breaking change: standard keyboard scrollable navigation bindings have been moved off `Widget` and onto a new base class for scrollable containers (see also below addition) https://github.com/Textualize/textual/issues/2332
+- `ScrollView` now inherits from `Scrollablecontainer` rather than `Widget` https://github.com/Textualize/textual/issues/2332
 
 ### Added
 

src/textual/scroll_view.py

@@ -7,11 +7,11 @@ from __future__ import annotations
 
 from rich.console import RenderableType
 
+from .containers import ScrollableContainer
 from .geometry import Size
-from .widget import Widget
 
 
-class ScrollView(Widget):
+class ScrollView(ScrollableContainer):
     """
     A base class for a Widget that handles it's own scrolling (i.e. doesn't rely
     on the compositor to render children).