[treemacs] Add persp-mode integration

CHANGELOG.develop

@@ -3090,6 +3090,7 @@ Other:
 - Deprecated =treemacs-use-collapsed-directories=. Flattening directories should
   be controlled by directly setting =treemacs-collapse-dirs=.
 - Fixed "width (un)locked" message appearing when treemacs is loaded.
+- Add =persp-mode= integration (thanks to Seong Yong-ju)
 **** Typescript
 - Call tsfmt with extension of current buffer for TSX formatting
   (thanks to Victor Andrée)

layers/+filetree/treemacs/packages.el

@@ -16,6 +16,7 @@
     treemacs
     (treemacs-evil :toggle (memq dotspacemacs-editing-style '(vim hybrid)))
     (treemacs-magit :requires magit)
+    (treemacs-persp :requires persp-mode)
     treemacs-projectile
     winum
     ))
@@ -28,7 +29,9 @@
 
 (defun treemacs/init-treemacs ()
   (use-package treemacs
-    :commands (treemacs-select-window treemacs--window-number-ten
+    :commands (treemacs-select-window
+               treemacs-select-scope-type
+               treemacs--window-number-ten
                treemacs-current-visibility)
     :defer t
     :init
@@ -91,6 +94,9 @@
     :defer t
     :init (require 'treemacs-projectile)))
 
+(defun treemacs/init-treemacs-persp ()
+  (use-package treemacs-persp :after treemacs))
+
 (defun treemacs/pre-init-winum ()
   (spacemacs|use-package-add-hook winum
     :post-config