Update Controls.js

Add `@deprecated` tag.

src/extras/Controls.js

@@ -84,7 +84,7 @@ class Controls extends EventDispatcher {
 
 		if ( element === undefined ) {
 
-			console.warn( 'THREE.Controls: connect() now requires an element.' );
+			console.warn( 'THREE.Controls: connect() now requires an element.' ); // @deprecated, the warning can be removed with r185
 			return;
 
 		}