Fixes to handling reference comments.

 - Revert most part of old behavior.
 - Do not handle reference comments as statements.
 - Handle reference comments only in special scanner state (assigned by parser at the beginning of file).
Parsing /// <...> as JSX elements but no more highlight.

* Fixed more failing tests that expect it to be emitted as comment.
* Removed highlighting support for reference comments though.

TODO: Reconsider highlighting in future on service side.