bug#60623: 30.0.50; Add forward-sentence with tree sitter support

[Drew Adams]

> > I'm not sure.  I think that maybe because the commands involved, and the
> > ones that implicitly will be impacted, such as kill-sentence and friends
> > it is best to stay with Sentences?  But a statement is the better term
> > wrt programming languages of course.  I hold no strong opinions here.
> 
> FWIW, while it may correspond to "statements" for some languages, it
> will correspond to other things in other languages (e.g. those that
> don't have a notion of "statement"), so it's probably best to stick to
> "sentence" here and then in the doc explain how that notion is expected
> to be mapped to notions that make sense for a given language.

I'm not following this thread.  But neither
"statement" nor "sentence" sounds appropriate for
what you're apparently talking about.  Both would
seem to be misleading.  Maybe you should add a new
THING type for just what you mean?