def-advice!->defadvice! & conform to new advice conventions

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.

modules/completion/company/config.el

@@ -27,7 +27,7 @@
     ;; Allow users to switch between backends on the fly. E.g. C-x C-s followed
     ;; by C-x C-n, will switch from `company-yasnippet' to
     ;; `company-dabbrev-code'.
-    (def-advice! +company-abort-previous-a (&rest _)
+    (defadvice! +company--abort-previous-a (&rest _)
       :before #'company-begin-backend
       (company-abort)))