Add dotspacemacs-server-socket-dir to dotfile template

core/templates/.spacemacs.template

@@ -370,6 +370,13 @@ It should only modify the values of Spacemacs settings."
    ;; (default nil)
    dotspacemacs-enable-server nil
 
+   ;; Set the emacs server socket location.
+   ;; If nil, uses whatever the Emacs default is, otherwise a directory path
+   ;; like \"~/.emacs.d/server\". It has no effect if
+   ;; `dotspacemacs-enable-server' is nil.
+   ;; (default nil)
+   dotspacemacs-server-socket-dir nil
+
    ;; If non-nil, advise quit functions to keep server open when quitting.
    ;; (default nil)
    dotspacemacs-persistent-server nil