Add underline for warnings

Author: oriori1703

init.lua

@@ -177,7 +177,7 @@ vim.diagnostic.config {
   update_in_insert = false,
   severity_sort = true,
   float = { border = 'rounded', source = 'if_many' },
-  underline = { severity = vim.diagnostic.severity.ERROR },
+  underline = { severity = { min = vim.diagnostic.severity.WARN } },
 
   -- Can switch between these as you prefer
   virtual_text = true, -- Text shows up at the end of the line