docs: Update RawKeyEvent references to KeyEvent (#3052) (#3053)

This PR fixes #3052 and updates deprecated type references in docs from
`RawKeyEvent` to `KeyEvent`.

Co-authored-by: Lukas Klingsbo <me@lukas.fyi>

doc/flame/inputs/keyboard_input.md

@@ -26,7 +26,7 @@ To make a `Game` sub class sensitive to key stroke, mix it with `KeyboardEvents`
 After that, it will be possible to override an `onKeyEvent` method.
 
 This method receives two parameters, first the
-[`RawKeyEvent`](https://api.flutter.dev/flutter/services/RawKeyEvent-class.html)
+[`KeyEvent`](https://api.flutter.dev/flutter/services/KeyEvent-class.html)
 that triggers the callback in the first place. The second is a set of the currently pressed
 [`LogicalKeyboardKey`](https://api.flutter.dev/flutter/services/LogicalKeyboardKey-class.html).
 
@@ -50,10 +50,10 @@ class MyGame extends FlameGame with KeyboardEvents {
   // ...
   @override
   KeyEventResult onKeyEvent(
-    RawKeyEvent event,
+    KeyEvent event,
     Set<LogicalKeyboardKey> keysPressed,
   ) {
-    final isKeyDown = event is RawKeyDownEvent;
+    final isKeyDown = event is KeyDownEvent;
 
     final isSpace = keysPressed.contains(LogicalKeyboardKey.space);
 
@@ -87,7 +87,7 @@ KeyboardHandlers must only be added to games that are mixed with `HasKeyboardHan
 After applying `KeyboardHandler`, it will be possible to override an `onKeyEvent` method.
 
 This method receives two parameters. First the
-[`RawKeyEvent`](https://api.flutter.dev/flutter/services/RawKeyEvent-class.html)
+[`KeyEvent`](https://api.flutter.dev/flutter/services/KeyEvent-class.html)
 that triggered the callback in the first place. The second is a set of the currently pressed
 [`LogicalKeyboardKey`](https://api.flutter.dev/flutter/services/LogicalKeyboardKey-class.html)s.
 

doc/tutorials/platformer/step_5.md

@@ -27,7 +27,7 @@ Now we can add a new method:
 
 ```dart
   @override
-  bool onKeyEvent(RawKeyEvent event, Set<LogicalKeyboardKey> keysPressed) {
+  bool onKeyEvent(KeyEvent event, Set<LogicalKeyboardKey> keysPressed) {
     return true;
   }
 ```
@@ -50,7 +50,7 @@ Now in our `onKeyEvent` method, we can register the key pressed by adding:
 
 ```dart
 @override
-  bool onKeyEvent(RawKeyEvent event, Set<LogicalKeyboardKey> keysPressed) {
+  bool onKeyEvent(KeyEvent event, Set<LogicalKeyboardKey> keysPressed) {
     horizontalDirection = 0;
     horizontalDirection += (keysPressed.contains(LogicalKeyboardKey.keyA) ||
             keysPressed.contains(LogicalKeyboardKey.arrowLeft))

examples/lib/stories/input/hardware_keyboard_example.dart

@@ -15,7 +15,7 @@ class HardwareKeyboardExample extends FlameGame {
   ''';
 
   /// The list of [KeyboardKey] components currently shown on the screen. This
-  /// list is re-generated on every RawKeyEvent. These components are also
+  /// list is re-generated on every KeyEvent. These components are also
   /// attached as children.
   List<KeyboardKey> _keyComponents = [];
 
@@ -221,9 +221,9 @@ class KeyboardKey extends PositionComponent {
   late final InlineTextElement textElement;
   late final RRect rect;
 
-  /// The RawKeyEvents may occur very fast, and out of sync with the game loop.
+  /// The KeyEvents may occur very fast, and out of sync with the game loop.
   /// On each such event we remove old KeyboardKey components, and add new ones.
-  /// However, since multiple RawKeyEvents may occur within a single game tick,
+  /// However, since multiple KeyEvents may occur within a single game tick,
   /// we end up adding/removing components many times within that tick, and for
   /// a brief moment there could be a situation that the old components still
   /// haven't been removed while the new ones were already added. In order to