Extend `XPENDING` and add support for `XGROUP {CREATECONSUMER,DESTROY,DELCONSUMER}`, `XINFO {CONSUMERS,GROUPS}`, `XCLAIM`

[sandyharvie]

As stated in the title, this PR adds support for the following commands:

• XGROUP {CREATECONSUMER,DESTROY,DELCONSUMER}
• XINFO {CONSUMERS,GROUPS}
• XCLAIM

In addition, I've added support for IDLE to the XPENDING implementation.

[alicebob]

Hi! Thanks for the PR. It looks good on first glance, but I'll need some time to have a proper look.

[alicebob]

PR looks good. I'm still trying to fix the problem with pre 1.17 Go, but I might also say the minimum version of miniredis will be 1.17 (which seems reasonable to me since it's the last version pre-generics).

[sandyharvie]

PR looks good. I'm still trying to fix the problem with pre 1.17 Go, but I might also say the minimum version of miniredis will be 1.17 (which seems reasonable to me since it's the last version pre-generics).

I think I've fixed the remaining issues in https://github.com/alicebob/miniredis/pull/281/commits/65aebb7f823482339cf846fa7bcc798f44f27e85, but feel free to revert the changes if you choose to make 1.17 the minimum supported version.

[alicebob]

Now CI is happy, thanks. Can you squash all the commits? I'll have a final look then (it's a big pr :)

[alicebob]

thanks!