Update to newer version of sublimehq/Packages

[fgelm01]

Would it be possible to update to update the testdata/Packages submodule to a newer version of https://github.com/sublimehq/Packages ?

It seems like the one that is there is about 7 years old.

My use case involves highlighting some C++20, and it is strange to not have the keywords requires, concept, and co_await not highlighted.

[keith-hall]

Unfortunately, no, this is not possible - more recent commits start using .sublime-syntax features that syntect doesn't support yet. #460
There's nothing to stop you from using a custom set of syntaxes though - i.e. with some patches applied on top. #168 may be of interest.

[fgelm01]

I see. Thank you for explaining.