Rename & change doom/update-pinned-package-declaration

+ Now named doom/update-pinned-package-form
+ If passed the prefix arg, the command now prompts for a remote commit
  to use.

core/autoload/packages.el

@@ -203,11 +203,11 @@ ones."
   (message "Reloading packages...DONE"))
 
 ;;;###autoload
-(defun doom/update-pinned-package-declaration ()
+(defun doom/update-pinned-package-form (&optional select)
   "Inserts or updates a `:pin' for the `package!' statement at point.
 
 Grabs the latest commit id of the package using 'git'."
-  (interactive)
+  (interactive "P")
   ;; REVIEW Better error handling
   ;; TODO Insert a new `package!' if no `package!' at poin
   (require 'straight)
@@ -215,6 +215,7 @@ Grabs the latest commit id of the package using 'git'."
     (while (and (atom (sexp-at-point))
                 (not (bolp)))
       (forward-sexp -1)))
+  (save-excursion
     (if (not (eq (sexp-at-point) 'package!))
         (user-error "Not on a `package!' call")
       (backward-char)
@@ -232,9 +233,12 @@ Grabs the latest commit id of the package using 'git'."
                       (straight-vc-git--encode-url upstream-repo upstream-host))))))
         (unless id
           (user-error "No id for %S package" name))
-      (let ((id (car (split-string id))))
+        (let* ((id (if select
+                       (car (split-string (completing-read "Commit: " (split-string id "\n" t))))
+                     (car (split-string id))))
+               (id (substring id 0 10)))
           (if (re-search-forward ":pin +\"\\([^\"]+\\)\"" (cdr (bounds-of-thing-at-point 'sexp)) t)
               (replace-match id t t nil 1)
             (thing-at-point--end-of-sexp)
             (backward-char)
-          (insert " :pin " (prin1-to-string id)))))))
+            (insert " :pin " (prin1-to-string id))))))))