Use vim-lsp instead of ale

rust.vim

@@ -1,4 +1,11 @@
 " No spell checking in code file
 autocmd BufNewFile,BufRead *.rs setlocal nospell
 
-
+if executable('rls')
+    " pip install rust-language-server
+    au User lsp_setup call lsp#register_server({
+        \ 'name': 'rls',
+        \ 'cmd': {server_info->['rls']},
+        \ 'allowlist': ['rust'],
+        \ })
+endif