refactor: (if|when)-let -> (if|when)-let*

With the former macros' future in the air (and likely to be targeted in
future, potentially breaking changes), I'll deal with this now than have
it bite me later.

Ref: https://lists.gnu.org/archive/html/emacs-devel/2024-10/msg00637.html

modules/lang/org/autoload/org-attach.el

@@ -19,7 +19,7 @@
   "TODO"
   (interactive)
   (require 'org-attach)
-  (if-let (dir (org-attach-dir))
+  (if-let* ((dir (org-attach-dir)))
       (pop-to-buffer
        ;; Rather than opening dired *and* image-dired windows, suppress them
        ;; both and open only the image-dired window.

modules/lang/org/autoload/org-link.el

@@ -341,7 +341,7 @@ exist, and `org-link' otherwise."
   "Interpret LINK as an URL to an image file."
   (when (and (image-type-from-file-name link)
              (not (eq org-display-remote-inline-images 'skip)))
-    (if-let (buf (url-retrieve-synchronously (concat protocol ":" link)))
+    (if-let* ((buf (url-retrieve-synchronously (concat protocol ":" link))))
         (with-current-buffer buf
           (goto-char (point-min))
           (re-search-forward "\r?\n\r?\n" nil t)