Give template strings a different classification type

[DanielRosenwasser]

At the time, we just used "stringLiteral" because it was such a PITA to sync between the managed side and whatnot. We never followed up on it. Prompted by #6508.

Open questions:

1. Do we want to classify ${ and } specially?
2. If we do want to classify ${ and } specially in templates, do we want to classify backticks?
3. What colors do we want to use in VS?

@derekcicerone @basarat

[derekcicerone-zz]

Thanks for checking. I don't have a strong opinion on the highlighting for string templates. It never hurts to have more specific classifications though - worst case we can keep coloring as strings. The syntax coloring I'd still really like is to distinguish between a normal comment and JSDoc.

[basarat]

I am very happy with what is there currently in the syntactic analyzer (the one between lexical and semantic) 🌹 that I am using as a work in progress in alm.tools