fix: error in command line mode(#20)

Author: haorenW1025

lua/diagnostic.lua

@@ -69,6 +69,7 @@ function M.diagnostics_loclist(local_result)
 end
 
 function M.publish_diagnostics(bufnr)
+  if vim.fn.getcmdwintype() == ':' then return end
   if #vim.lsp.buf_get_clients() == 0 then return end
   local result = M.bufferDiagnostic[bufnr]
   if result == nil then return end