Partial revert of r32376: don't strip whitespace from summaries. If you do, that...

Partial revert of r32376: don't strip whitespace from summaries.  If you do, that means that the default "/* Section name */ " summary loses its trailing space if you hit preview before submitting, which is noticeably inconsistent and annoying.  Maybe trim it on save, but I don't know if there's any point.