Media templates: Alter escaping regular expression to prevent it from aggresively consuming input meant for interpolation. see #22344, #21390.

git-svn-id: https://develop.svn.wordpress.org/trunk@22539 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/js/media-models.js

@@ -80,7 +80,7 @@ window.wp = window.wp || {};
 				options = {
 					evaluate:    /<#([\s\S]+?)#>/g,
 					interpolate: /\{\{\{([\s\S]+?)\}\}\}/g,
-					escape:      /\{\{([\s\S]+?)\}\}/g
+					escape:      /\{\{([^\}]+?)\}\}(?!\})/g
 				};
 
 			return function( data ) {