man/: SYNOPSIS: Don't highlight forward declarations of function parameters

man/: SYNOPSIS: Don't highlight forward declarations of function parameters

Previously, many people confused these for actual parameters, since it's
hard to distinguish a ',' from ';'.  By removing bold/italics from
these, it will be easier to distinguish them.

The cases have been found with a script:

	$ find -type f \
	| xargs grep -l '^\.TH ' \
	| sort \
	| xargs mansect SYNOPSIS \
	| man /dev/stdin \
	| grep -e '^[^ ]' -e '[^ ]( [^ )].*[^)];' \
	| less;

Reported-by: Mark Naughton <mnaughto@redhat.com>
Suggested-by: Mark Harris <mark.hsj@gmail.com>
Acked-by: Mark Naughton <mnaughto@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>