optional plurals

[frivoal]

If you have a <dfn> for a word that can be pluralized, such as <dfn>representative</dfn>, bikeshed will sucessfully autolink the singular [=representative=] as well as the plural [=representatives=], but it doesn't handle [=representative(s)=], which would be nice. Currently, what you can do is [=representative=](s), but typographically, that's not as nice, since the (s) will be outside of the autolinked term and of the way such terms are getting styled.