Add support for tagged html template strings

[emedvedev]

A companion PR to babel/babel-sublime#350, since the feature is missing there as well :)

Adds support for HTML highlighting inside template literals tagged with an html function. Support for this feature has been implemented in Babel highlighting for Atom for a while, and even GitHub highlights it like it's supposed to (thanks @DylanPiercey for pointing that out in babel/babel-sublime#138 (comment)):

const it = html`
  <div>hi</div>
`

It's also a fairly important part of Polymer starting from 2.4. As the Polymer documentation puts it:

Some text editors support HTML code highlighting in JavaScript template literals tagged with a function called html.

[emedvedev]

@Benvie would it be possible to merge this and update the package?

[Benvie]

Thanks for the heads up. I didn’t get a notification for this for some reason.

[jsilvermist]

@Benvie Any updates on this? With Polymer 3 just released not having this syntax highlighting is a major issue.