Renamed doc to docs and minor language fixes

docs/examples/keyboard/lib/main.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+import 'package:flame/game.dart';
+import 'package:flame/keyboard.dart';
+import 'package:flutter/services.dart';
+
+import 'dart:ui';
+
+void main() => runApp(MyGame().widget);
+
+class MyGame extends Game with KeyboardEvents {
+  static final Paint _white = Paint()..color = const Color(0xFFFFFFFF);
+
+  Rect _rect = const Rect.fromLTWH(0, 100, 100, 100);
+  int _dir = 0;
+
+  @override
+  void update(double dt) {
+    _rect = _rect.translate(
+      _dir * dt * 100,
+      0,
+    );
+  }
+
+  @override
+  void render(Canvas canvas) {
+    canvas.drawRect(_rect, _white);
+  }
+
+  @override
+  void onKeyEvent(e) {
+    final bool isKeyDown = e is RawKeyDownEvent;
+    if (e.data.keyLabel == "a") {
+      _dir = isKeyDown ? -1 : 0;
+    } else if (e.data.keyLabel == "d") {
+      _dir = isKeyDown ? 1 : 0;
+    }
+  }
+}