revlogv2: simplify and clarify the processing of each entry
As we add more entries and some of them has non trivial processing it seems
useful to make the processing leaner and clearly separated to simplify futures
patches.
Differential Revision: https://phab.mercurial-scm.org/D10773
#require rustfmt test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/..
$ RUSTFMT=$(rustup which --toolchain nightly-2020-10-04 rustfmt)
$ for f in `testrepohg files 'glob:**/*.rs'` ; do
> $RUSTFMT --check --edition=2018 --unstable-features --color=never $f
> done