Match using matchCompletionRegex

This is a bit of a hack since I should really be using the entire current line

package.json

@@ -55,7 +55,7 @@
         "c9"
     ],
     "c9plugins": {
-        "c9.ide.language": "#4428cfb1d2",
+        "c9.ide.language": "#3ed8ee7522",
         "c9.ide.language.css": "#ef8a28943e",
         "c9.ide.language.generic": "#77d43cfaf0",
         "c9.ide.language.html": "#99efa2853f",