Implement filtering by chat type

[KnorpelSenf]

TODO:

• narrow down context type
• add JSDoc

Closes #105.

[KnorpelSenf]

This is blocked by #100. The narrowed context for chat types should be exposed. Will wait in order to prevent merge conflicts.

[KnorpelSenf]

Types should ideally also reflect that channel posts are sent in channels, and messages aren't. There may be a lot more dependencies between these things. This will get a very complex type annotation, but it is probably worth it.

[KnorpelSenf]

Types should ideally also reflect that channel posts are sent in channels, and messages aren't. There may be a lot more dependencies between these things. This will get a very complex type annotation, but it is probably worth it.

In fact, this should rather be done in @grammyjs/types because grammY would automatically reflect these changes. Also, we never unset properties. It is good enough that they are optional, because user code cannot really break in that case anyway.

Can be merged as-is after an approval.

[KnorpelSenf]

Thanks for the review and the suggestion about optional types! I'll merge this as soon as we have a second approval :)

@all-contributors add @kolay-v for review

[allcontributors]

@KnorpelSenf

I've put up a pull request to add @kolay-v! 🎉

[EdJoPaTo]

I like this as it both simplifies some code and provides better typings. Worked in the bots I tried it both without changes and with using the new chatType method.

[KnorpelSenf]

Thanks for the reviews!