Supress diagnostics on @plugin and @source

packages/tailwindcss-language-server/src/language/cssServer.ts

@@ -381,7 +381,7 @@ async function validateTextDocument(textDocument: TextDocument): Promise<void> {
     .filter((diagnostic) => {
       if (
         diagnostic.code === 'unknownAtRules' &&
-        /Unknown at rule @(tailwind|apply|config|theme)/.test(diagnostic.message)
+        /Unknown at rule @(tailwind|apply|config|theme|plugin|source)/.test(diagnostic.message)
       ) {
         return false
       }