This commit does two things:
- Renames def-advice! to defadvice!, in the spirit of naming convenience
macros after the function/macro they enhance or replace.
- Correct the names of advice functions to indicate visibility and
intent. A public advice function like doom-set-jump-a is meant to be
used elsewhere. A private one like +dired--cleanup-header-line-a
shouldn't -- it likely won't work anywhere but the function(s) it was
made to advise.
