[Emacs mode] Only string and comment are colored

[amelieled]

(I suppose k3-mode.el file is deprecated)

I'm on Ubuntu (or on Debian) with only the file k-mode.el, but only string and comment are colored (the first one is brown and the second is grey).

I don't know why others features don't work.

[jzw2]

Set the variable k-custom-highlights-regex to something. There appears to be error because the initial value of nil is bad, unfortunately I don't know emacs-lisp well enough to know what the right way to fix it would be.