Putting a <!-- --> in plural<!-- -->s was an old hack used to fix
linking the symbol with gtk-doc when gtk-doc didn’t know about plural
forms. gtk-doc does now know about plural forms, so the hack can be
removed.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
If we have an input parameter (or return value) we need to use (nullable).
However, if it is an (inout) or (out) parameter, (optional) is sufficient.
It looks like (nullable) could be used for everything according to the
Annotation documentation, but (optional) is more specific.