Append empty value to inserted html attribute on completion

lib/ace/mode/html.js

@@ -326,7 +326,8 @@ function findTagName(iterator) {
             }
             return attributes.map(function(attribute){
                 return {
-                    value: attribute,
+                    caption: attribute,
+                    snippet: attribute + '="$0"',
                     meta: "attribute"
                 };
             });