update easygrep highlighting to be more like other options

In terms of integration into the plugin.

vim/bundle/easygrep

@@ -1 +1 @@
-Subproject commit 01fb7c005d757d9a88017d7893adb459ab5858bb
+Subproject commit 6c0fc0522aa7ae78d5e8bb01b02c5ebbe3222d1a