debugindex: introduce a concept of "verbose-only" column
We are about to add a bunch of new column and most of them are probably only
relevant to --verbose.
We add some more testing of the `--verbose` mode in a sidedata context.
#require rustfmt test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/..
Warning: Keep this in sync with hghave.py
$ RUSTFMT=$(rustup which --toolchain nightly-2021-11-02 rustfmt)
$ for f in `testrepohg files 'glob:**/*.rs'` ; do
> $RUSTFMT --check --edition=2018 --unstable-features --color=never $f
> done