When the first argument or arguments of a macro are opening delimiters

When the first argument or arguments of a macro are opening delimiters
(parentheses and/or square brackets), both modern groff and mandoc first
output those leading delimiters as plain text, then start the macro scope
after these opening delimiters.  This is similar to printing trailing
punctuation and trailing closing delimiters on a macro line outside and
after the macro scope.  For example, ".Sq ( text )" is "(`text')",
not "`(text)'".  Thus, we now need to quote leading opening delimiters
when we want them inside the macro scope.
These are the cases in src/bin.

"makes sense" jmc@