Merge: vim: look for `{ in deciding to highlight ffi language name. eg "C".

so `"C"` is now contextually highlighted.

Note: `\ze` means the end mark. What follows is looked for to be matched but is not considered in the token (some kind of lookahead)

Pull-Request: #1326
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>