BUG: Support remapping of non-simple binds

[meag]

Reported by drzel on Discord.

drzel: Not sure if this is relevant but I have my caps and escape keys swapped drzel: using https://github.com/susam/uncap drzel: but quake doesn't respect it

Need to add SDL keycodes to keyname_t entries in keys.c, then do the conversion through SDL? (would need tested to see if that would work)