support embedded hbs

[NullVoxPopuli]

Caveat: I'm not sure how to test this. I'm new to Atom

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

Try to support embedded hbs via template literals, as is demonstrated via:
https://hljs-glimmer.nullvoxpopuli.com/?sample=jsWithHbs

(this is used everywhere in testing, too)

Alternate Designs

?

Benefits

Handlebars developers (and consequently ember developers, even though ember doesn't use handlebars), will get syntax highlighting on hbs template strings

Possible Drawbacks

people get color?

Applicable Issues

[icecream17]

here's an example of adding a test:
https://github.com/atom/language-javascript/pull/686/files?authenticity_token=4VJRqGanlAImauIU7k1e3f1jPOVCh1%2Bx9NV80qiIWtduhIIrWuo6sUqt240IVZN3JgJxVVqVbULNJgrKzO%2FAhA%3D%3D&file-filters%5B%5D=.coffee#diff-ad1df1a6fb1e184c8294a94418c0dcba44b84968ae60b819ab60358361d4c8c1R633-R641

basically grammar.tokenizeLine whatever you want and then check if the tokens and scopes match

[icecream17]

Copied? (Btw, I added tests in a pr: NullVoxPopuli#1)

[NullVoxPopuli]

Thank you so much!