feat(lang): add rufo package for Ruby

As I'm not convinced formatting with rufo is good idea yet, this is
simply so I can play with it when I want to. It is not configured to
automatically format files on save.

modules/languages/siren-ruby.el

@@ -99,6 +99,17 @@
     (lsp-format-buffer-on-save-mode t)
     (lsp-deferred)))
 
+(use-package rufo
+  :defer t
+  :custom
+  (rufo-minor-mode-executable "rufo")
+  (rufo-minor-mode-use-bundler nil)
+  (rufo-minor-mode-debug-mode nil)
+
+  :init
+  (add-to-list 'safe-local-variable-values
+               '(rufo-minor-mode-use-bundler . t)))
+
 (use-package dap-ruby
   :straight dap-mode
   :after (ruby-mode dap-mode))