Merge pull request #3607 from mariusbutuc/few-typos

Fix a couple of typos in the documenting comments

src/layout/layout.js

@@ -181,7 +181,7 @@
   };
 
   /**
-   * Handles events of of drawer button.
+   * Handles events of drawer button.
    *
    * @param {Event} evt The event that fired.
    * @private

src/menu/menu.js

@@ -339,7 +339,7 @@
   };
 
   /**
-   * cleanup function to remove animation listeners.
+   * Cleanup function to remove animation listeners.
    *
    * @param {Event} evt
    * @private