Contribute source.postcss and source.css.postcss scopes

[xymopen]

This PR aims to provide source.postcss and source.css.postcss scopes for other extensions and close #6, #8.

Currently this would only benefit Volar (vuejs/language-tools#191) as Vetur (vuejs/vetur@d96067d) and Svelte (sveltejs/language-tools#1044) have chosen to bundle their own grammars.

[slavanossar]

Any chance we could get this merged @jonathantneal? Thanks!

[jonathantneal]

Yes. I will look into getting another release out, as well. Thank you, @xymopen !

[ghaschel]

Any news about the release with these changes? I am trying to add support to PostCSS in my extensions using your syntax highlighting scope.

[kotx]

Hi, is it possible to get a release published with these changes? It's been a while.

[slavanossar]

I had to set up a new computer a couple of weeks ago and was stumped why postcss highlighting was broken in Vue SFCs – it had been so long ago I completely forgot I had manually added the changes from this PR to the extension on my other computers. Only remembered after getting the latest notification on this thread.

Can we pretty please get a new release published @jonathantneal? Thanks!

[slavanossar]

@jonathantneal can we please get a new release, it's been over a year since it was merged. Thanks!