the patch subject becomes a bit outdated with this addition.

Right; I wanted to change it to something like "clarify `git bisect
run` syntax and other minor changes" but wanted to keep the title
concise.
I guess I could change it to just "clarify `git bisect` syntax" though
remove the "run").

the following two lines are already referencing placeholders
<term-new> and <term-old>

That's why I added it; that `(bad|new|<term-new>)` felt a bit awkward
with no previous explanation of what <term-new> was.

...now we have an inconsistency again since this text just uses the
generic <term>. However, I haven't convinced myself that we need to
care about this inconsistency.

I thought about that, but in THAT case it wasn't necessary because
<term-new> and <term-old> are never used there (and I wanted to avoid
making -h too long).  But it's true that it feels inconsistent; I may
add it just for the sake of consistency.

Overall, maybe I should leave that change to a separate patch, even if
it's a minor correction.  (This made more sense when I had in mind the
plan to move everything from description to synopsis so I would need
to touch all those lines anyway.)  The changes will be compatible
anyway (they're far away enough to not cause merge conflicts).  What
do you think?