fix(lsp): diagnostic codes already show by default (#4070)

avoid viewing duplicate diagnostic codes since they are now already shown
by default since neovim#21130

lua/lvim/lsp/config.lua

@@ -75,13 +75,6 @@ return {
       source = "always",
       header = "",
       prefix = "",
-      format = function(d)
-        local code = d.code or (d.user_data and d.user_data.lsp.code)
-        if code then
-          return string.format("%s [%s]", d.message, code):gsub("1. ", "")
-        end
-        return d.message
-      end,
     },
   },
   document_highlight = false,