Format extension registry: unsigned integer types (uint16, uint32, uint64)

[micolous]

I’m proposing to add the following unsigned integer types:

value	description	JSON data type
uint16	unsigned 16-bit integer	number
uint32	unsigned 32-bit integer	number
uint64	unsigned 64-bit integer	number, string (same caveats as int64)

The uint32 and uint64 formats are already in use by gnostic.

This is effectively a repeat of #2617, now that there is an extension registry, as it looks like only uint8 was added when that registry was created.

[handrews]

@micolous I honestly thought we had these- a PR would be welcome, just follow what was done for uint8. Or if you don't have time to do that, someone will get to this eventually (perhaps @baywet or @mikekistler)

[baywet]

@handrews If my memory serves me right, I initially had added it in my PRs, but we removed them during review because it was not part of the types requested by users on existing issues at the time.
Happy to take this on, or maybe @micolous wants to submit a pull request?

[micolous]

Having a look at #3167, it looks like the way to add an extra format is with a PR targeting the gh-pages branch, rather than any of the other "main" v3.x branches, correct?

[baywet]

That's correct! Let me know if you have any additional comments or questions.

[baywet]

Added through #4585

[lornajane]

Merged into the gh-pages branch