nvim: init: Do not use underline for diagnostic

nvim/.config/nvim/init.lua

@@ -81,7 +81,7 @@ vim.g.matchup_surround_enabled     = 1
 vim.api.nvim_command('set rtp-=/usr/share/vim/vimfiles')
 -- Disable virtual text for all diagnostics
 vim.diagnostic.config({
-  underline        = true,
+  underline        = false,
   signs            = true,
   virtual_text     = false,
   update_in_insert = false,