doc: cross-reference macro parameter concatenation with %[...]
doc: cross-reference macro parameter concatenation with %[...]

Explicitly document that %[...] and macro parameters concatenate the
same way, and cross-reference the two.

Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>

turingstudio/nasm,Distrotech/nasm,letolabs/nasm,turingstudio/nasm,turingstudio/nasm,projedi/nasm,techkey/nasm,turingstudio/nasm,Distrotech/nasm,techkey/nasm,projedi/nasm,letolabs/nasm,techkey/nasm,techkey/nasm,letolabs/nasm,Distrotech/nasm,projedi/nasm,projedi/nasm,projedi/nasm,techkey/nasm,Distrotech/nasm