Prettier Integration

It'd be nice to integrate Prettier into Wild Web Developer to enable features such as CSS formatting.

Originally, I wanted to propose having a Node.JS project builder, which would use the embedded Node.JS instance from Wild Web Developer to allow running Node applications as a build action. This would allow users to create a package.json for their workspace, add prettier as a dev-dependency and run prettier to format on save/automatic build.

However there are issues with this approach:

• A user might want to format CSS and not use a package.json
• Most users who would want to run Node tools such as prettier will most likely have Node on their system. Using the internal/embedded Node from Wild Web Developer might cause differences/issues, and there is a maintance cost for adding options (such as use internal/external node for Node.JS project builder)

So instead, it might be desirable to integrate Prettier directly into Wild Web Developer, and have it run on format.

Prettier is configurable with a configuration file, which will give users nice options such as ignoring certain files when formatting, using single/double quotes, etc.

Prettier is already being used in Spectrum Theme as a project build action.

Start by reviewing the proposed package.json and the format-on-save or automatic-build entry points; the issue does not name specific repository files or tests. Read Prettier's configuration and options documentation, then define how direct integration should run formatting and honor project configuration before implementing it.