[C23] Update status page for TS 18661 integration

[AaronBallman]

WG14 N2401 was removed from the list because it was library-only changes that don't impact the compiler.

Everything having to do with decimal floating-point types was changed to No because we do not currently have any support for those.

WG14 N2314 remains Unknown because it has changes to Annex F for binary floating-point types.

[AaronBallman]

Up for review just to make sure there's not been work happening that I wasn't aware of, and to verify the removal of N2401.

[jcranmer-intel]

It might be better to list most of these as "N/A" rather than "No", for the simple reason that decimal floating point is an optional feature we do not support. Or maybe just a footnote saying something to that effect?

[jcranmer-intel]

N2580 looks to be an editorial change rather than a substantive change that can or cannot be conformed to.

[AaronBallman]

Okay, since this is under an omnibus feature category, I'll just remove this entry.

[jcranmer-intel]

This looks to be vacuously yes: you need both Annex F conformance (which clang doesn't claim yet) and non-0 DEC_EVAL_METHOD (which I think @tahonermann et al aren't planning on) for this to matter.

[AaronBallman]

Awesome, thanks!

[AaronBallman]

It might be better to list most of these as "N/A" rather than "No", for the simple reason that decimal floating point is an optional feature we do not support. Or maybe just a footnote saying something to that effect?

I think eventually I'd like to split out optional annexes and TSes to a separate table so we can track whether they're available in Clang or not rather than whether we conform or not. But for right now, I'd say let's stick with No because it's clear that we don't support them rather than N/A which somewhat implies that we don't need to make compiler changes to support them.