Add support for `non-sealed` keyword about language-java

[sadikovi]

We support tree-sitter now, textmate grammar is sort of deprecated at this point. Most of the grammar comes from tree-sitter-java, so you would have to check if they handle the keyword there.

[fbricon]

#234 was merged just 10 days ago, so I didn't expect it was deprecated already ;-)

Will look at tree-sitter-java, but if it doesn't support the latest Java 15 syntax, does it mean the content from #234 will be lost?

[Aerijo]

(for context) The deprecation seems fast in isolation, but the general policy across Atom for a long time now has been to focus only on the Tree-sitter version if it exists. And as of 10 days ago it now exists here too.

The TextMate grammars are still included and can be used by disabling Tree-sitter (either globally or Java specific). I guess in this case it's up to @sadikovi, but with other grammars with Tree-sitter support PRs for TextMate have been closed simply because Tree-sitter exists for them, and anyone still relying on the TextMate grammar was encouraged to maintain a fork of their own.

Support for the keywords may still need to be added here; Tree-sitter will parse a lot, but even if it parses those keywords some tokens might need to be discriminated further by Atom in order to apply different syntax highlighting (e.g., TS might parse public and protected as the same kind of token, so Atom would need to identify them like it does here). I haven't looked at any of the Java grammars though, so it's possible the TS Java parser doesn't parse them yet too.

[sadikovi]

Thanks @Aerijo! It simply took me one year to finally merge the tree-sitter PR 😄 . I will continue maintaining both versions as much as I can, while tree-sitter is catching up with the textmate grammar. I will be focusing on that mostly.

@fbricon Please, don't feel discouraged and do report suggestions and issues or even open PRs! All I was trying to say in my earlier post was that tree-sitter bugs and features will take priority over the textmate grammar now.

I will open the PR for the textmate to add non-sealed keyword later this week.