refactor(cli): rename 'doom purge' -> 'doom gc'

'doom purge' is now deprecated.

Also changes 'doom sync's -p option to --gc. Since GCing causes the loss
of historical data, I'd rather it be a long option to make it a little
harder to do accidentally.

bin/doom

@@ -271,7 +271,7 @@ SEE ALSO:
     (defcli-autoload! ((profiles profile)))
     (defcli-autoload! ((upgrade up)))
     (defcli-autoload! (env))
-    (defcli-autoload! ((build b purge p rollback)) "packages")
+    (defcli-autoload! ((build b purge p gc rollback)) "packages")
     (defcli-autoload! ((install i)))
 
     ;; TODO Post-3.0 commands

lisp/cli/packages.el

@@ -15,9 +15,10 @@
 
 (defcli-obsolete! ((build b)) (sync "--rebuild") "v3.0.0")
 
+(defcli-obsolete! ((purge p)) (gc) "v3.0.0")
 
 ;; TODO Rename to "doom gc" and move to its own file
-(defcli! ((purge p))
+(defcli! (gc)
     ((nobuilds-p  ("-b" "--no-builds")  "Don't purge unneeded (built) packages")
      (noelpa-p    ("-p" "--no-elpa")    "Don't purge ELPA packages")
      (norepos-p   ("-r" "--no-repos")   "Don't purge unused straight repos")

lisp/cli/sync.el

@@ -24,7 +24,7 @@
     ((noenvvar? ("-e") "Don't regenerate the envvar file")
      (update?   ("-u") "Update all installed packages after syncing")
      (noupdate? ("-U") "Don't update any packages")
-     (purge?    ("-p") "Purge orphaned package repos & regraft them")
+     (purge?    ("--gc") "Purge orphaned package repos & regraft them")
      (jobs      ("-j" "--jobs" num) "How many threads to use for native compilation")
      (rebuild?  ("-b" "--rebuild") "Rebuild, compile, & symlink installed packages")
      (auto?     ("-B") "Rebuild packages, but only if necessary")