vertico: various refactors...

- unify `map!` statements when possible
- rename `+vertico--embark-target-package!` to
  `+vertico--embark-target-package` and autoload it
- set `completion-in-region-function` to a wrapper function instead of
  changing it with a hook
- use `:override` advice instead of `fset` for `multi-occur`
- document what `vertico-directory-tidy` does
- move `:init` contents to `:config` when possible

modules/completion/vertico/autoload/vertico.el

@@ -92,6 +92,15 @@ If ARG (universal argument), include all files, even hidden or compressed ones."
                      (expand-file-name new-path))))))
       (call-interactively 'backward-delete-char))))
 
+(defun +vertico--embark-target-package ()
+    "Targets Doom's package! statements and returns the package name"
+    (when (or (derived-mode-p 'emacs-lisp-mode) (derived-mode-p 'org-mode))
+      (save-excursion
+        (search-backward "(")
+        (when (looking-at "(\\s-*package!\\s-*\\(\\(\\sw\\|\\s_\\)+\\)\\s-*")
+          (let ((pkg (match-string 1)))
+            (set-text-properties 0 (length pkg) nil pkg)
+            `(package . ,pkg))))))
 
 ;;;###autoload
 (defun +vertico/embark-export-write ()