Docs: Replace @returns tag in wp-admin/js/post.js with @return.

Per the documentation standards, `@returns` is an unsupported synonym, `@return` should be used instead.

Follow-up to [46800], [48232].

See #49572.

git-svn-id: https://develop.svn.wordpress.org/trunk@48298 602fd350-edb4-49c9-b593-d223f7449a82

src/js/_enqueues/admin/post.js

@@ -1228,7 +1228,7 @@ jQuery(document).ready( function($) {
 	 *
 	 * @param {MouseEvent} event A click event.
 	 *
-	 * @returns {void}
+	 * @return {void}
 	 */
 	copyAttachmentURLClipboard.on( 'success', function( event ) {
 		var triggerElement = $( event.trigger ),