fixup! refactor: event managers

Author: wagnermaciel

src/cdk-experimental/ui-patterns/behaviors/event-manager/keyboard-event-manager.ts

@@ -16,6 +16,12 @@ import {
   ModifierKey,
 } from './event-manager';
 
+/**
+ * Used to represent a keycode.
+ *
+ * This is used to match whether an events keycode should be handled. The ability to match using a
+ * string, Signal, or Regexp gives us more flexibility when authoring event handlers.
+ */
 type KeyCode = string | Signal<string> | RegExp;
 
 /**