bashrc: remove $LANG adjustment

My patch to `tree` has been accepted, so this is no longer neccessary.

Ref: 7e1d01fb4bffea0800e6a7559974f72ff02388ba
bashrc: load kc.sh unconditionally

It's tiny, no point in delaying it and forcing me to reload .bashrc the
first time I compile pklist... Actually, this be even faster than the
$PATH check.
bash/prompt: guard against unknown signals and stuff
git/config: add `git uncommit`