Re: git add intent-to-add then git add patch no longer allows edit

Johannes Schindelin [off-list ref] writes:

Thanks for reminding me, I did not really think about it anymore. The
built-in `git add -i`/`git add -p` has been available since v2.25.0. Since
v2.26.0, we also respect that flag in the `-p` modes of `checkout`,
`stash`, etc

That is 9a5315ed (Merge branch 'js/patch-mode-in-others-in-c', 2020-02-05)

And from the way at least _I_ read the commit log, it seems that the code
has been pretty stable (except for that bug fix where `e` was allowed by
mistake).

As long as it has been widely used, that is.  I do not think we
deeply mind a bug like the `e` one that does not affect the utility
or the correctness of the command that much.  If we do not flip the
"use the built-in variant" for those with feature.experimental we
really should do so to widen the canarying population immediately.