Consider a normative references chapter #2316

ISO standards have a mandatory Normative References chapter. I considered this a lot in the past, but never got around to adding it. There's not a lot that would necessarily be listed, but if we really want to be precise about how things work, it would cover those bases.

Some examples:

• The specific Unicode standard is already documented in the identifiers chapter, but could/should also be included in the references.
• The specific C specification we are working against. For example, things like C-variadics refer to specific C features without specifying which C standard.
• Unwinding refers to C++ without referring to anything specific (I'm not sure if this necessary, see this thread).
• Inline assembly refers to LLVM, and using its syntax, without specifying which LLVM.
• The ABI list refers to specific documentation and standards.

I don't know what exactly makes sense to include. And I'm not sure how valuable it would be, and would it be worth the maintenance cost.