(Java) Java 17 sealed keywords not implemented

[thiccaxe]

With the release of Java 17 being an LTS, it seems proper to support the new sealed keyword.
However, the new non-sealed keyword brings some issues, that while I have attempted to fix, seem best suited for someone more familiar with the highlightjs library.

Sample Code or Instructions to Reproduce
sample js fiddle

Expected behavior
the sealed keyword should be highlighted, and as more hyphenated keywords may come to java in the future, some structure
may be useful for non-sealed and the like.

[joshgoebel]

I think what you have already can be converted into a workable PR.

[joshgoebel]

Ping.

[joshgoebel]

Ping.