Ticket #36735: 36735.3.patch

src/wp-includes/js/shortcode.js

@@ -327 +327 @@
                                 text += ' ' + attr;
 
                                 // Use empty attribute notation where possible.
-                                if ( '' === value ) {
+                                if ( '' === value && 'alt' !== attr ) {
                                         return;
                                 }