refactor(workspaces): +workspace/delete: rename to +workspace/kill

To be more consistent with other uses of the verb in the Emacs
ecosystem. Also done in preparation for a new +workspaces/delete command
for #7869.

Ref: #7869

modules/app/irc/autoload/irc.el

@@ -60,7 +60,7 @@ workspace for it."
     (mapc #'kill-buffer (doom-buffers-in-mode 'circe-mode (buffer-list) t))
     (when (modulep! :ui workspaces)
       (when (equal (+workspace-current-name) +irc--workspace-name)
-        (+workspace/delete +irc--workspace-name)))))
+        (+workspace/kill +irc--workspace-name)))))
 
 ;;;###autoload
 (defun +irc/jump-to-channel (&optional this-server)