Typo in AbstractMemberWriter.addModifiers(Element member, Content htmltree) doc

[Christoph Dreis]

Hi Jon,

> Since this is "just" a minor typo in the doc comment for an internal API,
it does not seem worth sponsoring
> this as a patch in its own right.  We already have some work in progress
on that file currently being reviewed;
> I'll fix the typo as part of that, if that's OK with you.

Thanks. I don't mind.

Cheers,
Christoph