refactor(lib): doom-debug-mode: make verbosity selective

Now `doom-debug-mode` manipulates `doom-log-level` if you activate it
with a prefix arg, setting it to 1 by default, reducing its verbosity
and cutting down on noise in the logs.

modules/editor/snippets/config.el

@@ -31,7 +31,7 @@
   (add-transient-hook! #'company-yasnippet (require 'yasnippet))
 
   :config
-  (add-to-list 'doom-debug-variables '(yas-verbosity . 3))
+  (set-debug-variable! 'yas-verbosity 3)
 
   ;; Allow private snippets in DOOMDIR/snippets
   (add-to-list 'yas-snippet-dirs '+snippets-dir)