In interactive commands, allow the user to provide one-letter
input with a single key (i.e., without hitting enter).
Currently this is used by the `--patch` mode of
- linkgit:git-add[1], linkgit:git-checkout[1], linkgit:git-commit[1],
+ linkgit:git-add[1], linkgit:git-checkout[1],
+ linkgit:git-restore[1], linkgit:git-commit[1],
linkgit:git-reset[1], and linkgit:git-stash[1]. Note that this
setting is silently ignored if portable keystroke input
is not available; requires the Perl module Term::ReadKey.