vec (+swizzle) and annotated_arg should define their binary operators as hidden friends

[rolandschulz]

Both vec (+swizzle) and annotated_arg don't define the their binary operators as hidden friends. For vec the spec is clear that it should be a hidden friend. For annotated_arg we should make this clear.

Originally posted by @rolandschulz in https://github.com/intel/llvm/pull/11971#discussion_r1416679574

[steffenlarsen]

For vec and swizzle this is addressed in https://github.com/intel/llvm/pull/12396.

[steffenlarsen]

These have been addressed:

• vec: https://github.com/intel/llvm/pull/12396
• Swizzles: https://github.com/intel/llvm/pull/13012
• annotated_arg: https://github.com/intel/llvm/pull/12232

@rolandschulz - I will close this. Please reopen if you believe we missed something.