[JavaScript] Problem with = function syntax highlighting

[ahwayakchih]

= character is incorrectly highlighted when used in variable = function expression scenario:

var t2 = function test () {};
var t3 = () => 1;

Please notice how = is getting the same color as a function and variable names when using function f () syntax, but stays white when using new () => ("arrow function") syntax. I believe it should stay white in both cases.

(issue extracted from #141)

[ahwayakchih]

Found out it was a problem with theme file.