Check capability is dict (#675)

Author: mattn

autoload/lsp/ui/vim/completion.vim

@@ -128,6 +128,7 @@ function! s:resolve_completion_item(completion_item, server_name) abort
   " check server capabilities.
   let l:capabilities = lsp#get_server_capabilities(a:server_name)
   if !has_key(l:capabilities, 'completionProvider')
+        \ || type(l:capabilities['completionProvider']) != v:t_dict
         \ || !has_key(l:capabilities['completionProvider'], 'resolveProvider')
         \ || !l:capabilities['completionProvider']['resolveProvider']
     return a:completion_item