feat(format): add :lang erlang formatter

modules/lang/erlang/config.el

@@ -5,6 +5,8 @@
   :mode ("/rebar\\.config\\(?:\\.script\\)?\\'" . erlang-mode)
   :mode ("/\\(?:app\\|sys\\)\\.config\\'" . erlang-mode)
   :config
+  (when (executable-find "efmt")
+    (set-formatter! 'efmt '("efmt" "-") :modes '(erlang-mode)))
   (when (modulep! +lsp)
     (add-hook 'erlang-mode-local-vars-hook #'lsp! 'append))
 

modules/lang/erlang/doctor.el

@@ -4,3 +4,7 @@
 (assert! (or (not (modulep! +lsp))
              (modulep! :tools lsp))
          "This module requires (:tools lsp)")
+
+(when (modulep! :editor format)
+  (unless (executable-find "efmt")
+    (warn! "Couldn't find efmt. Formatting will be disabled.")))