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/editor/multiple-cursors/config.el

@@ -107,7 +107,7 @@
 
     ;; When running edit-lines, point will return (position + 1) as a result of
     ;; how evil deals with regions
-    (def-advice! +multiple-cursors-adjust-mark-for-evil-a (&rest _)
+    (defadvice! +multiple--cursors-adjust-mark-for-evil-a (&rest _)
       :before #'mc/edit-lines
       (when (and (bound-and-true-p evil-mode)
                  (not (memq evil-state '(insert emacs))))