util/find-doc-nits: relax some SYNOPSIS checks

util/find-doc-nits: relax some SYNOPSIS checks

-   The check that disallowed space before the argument list in a
    function typedef is tentatively removed, allowing this kind of
    construction:

    typedef int (fantastically_long_name_breaks_80char_limit)
        (fantastically_long_name_breaks_80char_limit *something);

-   Accept the following style of function signature:

    typedef TYPE (NAME)(args...)

-   Accept space between '#' and 'defined' / 'undef'

-   Accept other spaces than SPC in argument list comma check,
    allowing declaration with line breaks.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/12452)