[colorize_nicks.py] Mentioning nick "F1" breaks line prefix

[sim642]

Being in a channel with someone with the nick "F1". If that nick gets mentioned, their prefix will be broken, i.e. "F10" prepended:

It seems like the script is interfering with a color code in the line prefix.

Unloading colorize_nicks.py solves the issue. The problem can currently be avoided by adding "F1" to colorize_nicks.look.blacklist_nicks.

Brought to my attention by lunchdump in #weechat.