rewriteutil: replace "null changeset" by "the null revision" in error message
The evolve extension uses "the null revision" and we seem to use that
term much more frequently in core too.
Differential Revision: https://phab.mercurial-scm.org/D10514
$ . "$TESTDIR/narrow-library.sh"
$ hg init repo
$ cd repo
$ cat << EOF > .hg/store/narrowspec
> [include]
> path:foo
> [exclude]
> EOF
$ cp .hg/store/narrowspec .hg/narrowspec.dirstate
$ echo treemanifest >> .hg/requires
$ echo narrowhg-experimental >> .hg/requires
$ mkdir -p foo/bar
$ echo b > foo/f
$ echo c > foo/bar/f
$ hg commit -Am hi
adding foo/bar/f
adding foo/f
$ hg debugindex -m
rev linkrev nodeid p1 p2
0 0 14a5d056d75a 000000000000 000000000000
$ hg debugindex --dir foo
rev linkrev nodeid p1 p2
0 0 e635c7857aef 000000000000 000000000000
$ hg debugindex --dir foo/
rev linkrev nodeid p1 p2
0 0 e635c7857aef 000000000000 000000000000
$ hg debugindex --dir foo/bar
rev linkrev nodeid p1 p2
0 0 e091d4224761 000000000000 000000000000
$ hg debugindex --dir foo/bar/
rev linkrev nodeid p1 p2
0 0 e091d4224761 000000000000 000000000000
$ hg debugdata -m 0
foo\x00e635c7857aef92ac761ce5741a99da159abbbb24t (esc)
$ hg debugdata --dir foo 0
bar\x00e091d42247613adff5d41b67f15fe7189ee97b39t (esc)
f\x001e88685f5ddec574a34c70af492f95b6debc8741 (esc)
$ hg debugdata --dir foo/ 0
bar\x00e091d42247613adff5d41b67f15fe7189ee97b39t (esc)
f\x001e88685f5ddec574a34c70af492f95b6debc8741 (esc)
$ hg debugdata --dir foo/bar 0
f\x00149da44f2a4e14f488b7bd4157945a9837408c00 (esc)
$ hg debugdata --dir foo/bar/ 0
f\x00149da44f2a4e14f488b7bd4157945a9837408c00 (esc)