update readme

Author: bradlc

packages/vscode-tailwindcss/README.md

@@ -127,3 +127,4 @@ If you’re having issues getting the IntelliSense features to activate, there a
 - Ensure that you have a Tailwind config file in your workspace and that this is named `tailwind.config.js`. Check out the Tailwind documentation for details on [creating a config file](https://tailwindcss.com/docs/installation#create-your-configuration-file).
 - Ensure that the `tailwindcss` module is installed in your workspace, via `npm`, `yarn`, or `pnpm`.
 - Make sure your VS Code settings aren’t causing your Tailwind config file to be excluded from search, for example via the `search.exclude` setting.
+- Take a look at the language server output by running the `Tailwind CSS: Show Output` command from the command palette. This may show errors that are preventing the extension from activating.