Support syntax highlighting for embedded JS and C++

[rrudakov]

Close #23

ClojureScript:

Jank:

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• The commits are consistent with our contribution guidelines.

• You've run M-x checkdoc and fixed any warnings in the code you've written.
• You've updated the changelog (if adding/changing user-visible functionality).
• You've updated the readme (if adding/changing user-visible functionality).

Thanks!

[bbatsov]

Looks great to me. Fantastic work!

More features that are unique to clojure-ts-mode will encourage more people to try it out.

[rrudakov]

More features that are unique to clojure-ts-mode will encourage more people to try it out.

Maybe after next release we should encourage users to try it out. It would be great to receive some feedback and bug reports.