feat(tw): Add IntelliSense settings for Tailwind CSS VS Code plugin

[Tobbe]

This PR adds some Redwood specific settings for the Tailwind CSS IntelliSense plugin for VS Code.

More specifically it adds intellisense and color support for not only className (which is enabled by default), but also for activeClassName and errorClassName, which are two css class name props we use in Redwood

Here are docs for the setting I'm using:
https://marketplace.visualstudio.com/items?itemName=bradlc.vscode-tailwindcss#:~:text=tailwindCSS.classAttributes

Before

After

Manual Instructions

If you already have TW set up and want to enable this, open .vscode/settings.json and add this:

"tailwindCSS": {
  "classAttributes": ["class", "className", "activeClassName", "errorClassName"]
}