Improve lifecycle docs (#76021)

packages/flutter/lib/src/foundation/node.dart

@@ -87,6 +87,9 @@ class AbstractNode {
   /// Subclasses with children should override this method to first call their
   /// inherited [attach] method, and then [attach] all their children to the
   /// same [owner].
+  ///
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.attach(owner)`.
   @mustCallSuper
   void attach(covariant Object owner) {
     assert(owner != null);
@@ -101,6 +104,9 @@ class AbstractNode {
   ///
   /// Subclasses with children should override this method to first call their
   /// inherited [detach] method, and then [detach] all their children.
+  ///
+  /// Implementations of this method should end with a call to the inherited
+  /// method, as in `super.detach()`.
   @mustCallSuper
   void detach() {
     assert(_owner != null);

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

@@ -2583,8 +2583,8 @@ abstract class RenderBox extends RenderObject {
   /// object you can determine the [PointerDownEvent]'s position in local coordinates.
   /// (This is useful because [PointerEvent.position] is in global coordinates.)
   ///
-  /// If you override this, consider calling [debugHandleEvent] as follows, so
-  /// that you can support [debugPaintPointersEnabled]:
+  /// Implementations of this method should call [debugHandleEvent] as follows,
+  /// so that they support [debugPaintPointersEnabled]:
   ///
   /// ```dart
   /// @override

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

@@ -242,8 +242,8 @@ abstract class ViewportOffset extends ChangeNotifier {
   /// the [State] base class calls [debugFillDescription] to collect useful
   /// information from subclasses to incorporate into its return value.
   ///
-  /// If you override this, make sure to start your method with a call to
-  /// `super.debugFillDescription(description)`.
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.debugFillDescription(description)`.
   @mustCallSuper
   void debugFillDescription(List<String> description) {
     if (hasPixels) {

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

@@ -979,8 +979,8 @@ abstract class State<T extends StatefulWidget> with Diagnosticable {
   /// following this method, and [BuildContext.dependOnInheritedWidgetOfExactType] can
   /// be used there.
   ///
-  /// If you override this, make sure your method starts with a call to
-  /// super.initState().
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.initState()`.
   @protected
   @mustCallSuper
   void initState() {
@@ -1003,8 +1003,8 @@ abstract class State<T extends StatefulWidget> with Diagnosticable {
   ///
   /// {@macro flutter.widgets.State.initState}
   ///
-  /// If you override this, make sure your method starts with a call to
-  /// super.didUpdateWidget(oldWidget).
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.didUpdateWidget(oldWidget)`.
   @mustCallSuper
   @protected
   void didUpdateWidget(covariant T oldWidget) { }
@@ -1147,8 +1147,8 @@ abstract class State<T extends StatefulWidget> with Diagnosticable {
   /// this object and other elements in the tree (e.g. if you have provided an
   /// ancestor with a pointer to a descendant's [RenderObject]).
   ///
-  /// If you override this, make sure to end your method with a call to
-  /// super.deactivate().
+  /// Implementations of this method should end with a call to the inherited
+  /// method, as in `super.deactivate()`.
   ///
   /// See also:
   ///
@@ -1171,8 +1171,8 @@ abstract class State<T extends StatefulWidget> with Diagnosticable {
   ///
   /// {@macro flutter.widgets.State.initState}
   ///
-  /// If you override this, make sure to end your method with a call to
-  /// super.dispose().
+  /// Implementations of this method should end with a call to the inherited
+  /// method, as in `super.dispose()`.
   ///
   /// See also:
   ///
@@ -3406,6 +3406,9 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   /// [update], [visitChildren], [RenderObjectElement.insertRenderObjectChild],
   /// [RenderObjectElement.moveRenderObjectChild], and
   /// [RenderObjectElement.removeRenderObjectChild].
+  ///
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.mount(parent, newSlot)`.
   @mustCallSuper
   void mount(Element? parent, dynamic newSlot) {
     assert(_lifecycleState == _ElementLifecycle.initial);
@@ -3725,6 +3728,9 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   /// lifecycle state). Instead, the framework calls [mount] in that situation.
   ///
   /// See the lifecycle documentation for [Element] for additional information.
+  ///
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.activate()`.
   @mustCallSuper
   void activate() {
     assert(_lifecycleState == _ElementLifecycle.inactive);
@@ -3756,6 +3762,9 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   /// This is (indirectly) called by [deactivateChild].
   ///
   /// See the lifecycle documentation for [Element] for additional information.
+  ///
+  /// Implementations of this method should end with a call to the inherited
+  /// method, as in `super.deactivate()`.
   @mustCallSuper
   void deactivate() {
     assert(_lifecycleState == _ElementLifecycle.active);
@@ -3794,6 +3803,9 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   /// the tree again.
   ///
   /// See the lifecycle documentation for [Element] for additional information.
+  ///
+  /// Implementations of this method should end with a call to the inherited
+  /// method, as in `super.unmount()`.
   @mustCallSuper
   void unmount() {
     assert(_lifecycleState == _ElementLifecycle.inactive);

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

@@ -152,8 +152,8 @@ abstract class Notification {
   /// the [Notification] base class calls [debugFillDescription] to collect
   /// useful information from subclasses to incorporate into its return value.
   ///
-  /// If you override this, make sure to start your method with a call to
-  /// `super.debugFillDescription(description)`.
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.debugFillDescription(description)`.
   @protected
   @mustCallSuper
   void debugFillDescription(List<String> description) { }

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

@@ -255,8 +255,8 @@ class ScrollController extends ChangeNotifier {
   /// the [ScrollController] base class calls [debugFillDescription] to collect
   /// useful information from subclasses to incorporate into its return value.
   ///
-  /// If you override this, make sure to start your method with a call to
-  /// `super.debugFillDescription(description)`.
+  /// Implementations of this method should start with a call to the inherited
+  /// method, as in `super.debugFillDescription(description)`.
   @mustCallSuper
   void debugFillDescription(List<String> description) {
     if (debugLabel != null)