Fix #1970: don't count treemacs as a "popup"

And remove its popup rule.

It isn't being caught by the popup system in the first place, so this is
all a charade.

modules/ui/popup/autoload/popup.el

@@ -181,8 +181,7 @@ and enables `+popup-buffer-mode'."
     (let ((window (or window (selected-window))))
       (and (windowp window)
            (window-live-p window)
-           (or (window-parameter window 'popup)
-               (window-parameter window 'no-other-window))
+           (window-parameter window 'popup)
            window))))
 
 ;;;###autoload

modules/ui/treemacs/config.el

@@ -8,12 +8,6 @@
 
 
 (after! treemacs
-  (set-popup-rule! "^ \\*Treemacs"
-    :side treemacs-position
-    :size treemacs-width
-    :quit nil
-    :ttl 0)
-
   ;; Don't follow the cursor
   (treemacs-follow-mode -1)