rust-changelog: don't skip empty lines when iterating over changeset lines
The first empty line in the changeset indicates the end of headers and
beginning of description. Callers can't know figure out where that
position is if empty lines are skipped.
Differential Revision: https://phab.mercurial-scm.org/D12426
Tests that the exit code is as expected when ui.detailed-exit-code is *not*
enabled.
$ cat >> $HGRCPATH << EOF
> [ui]
> detailed-exit-code=no
> EOF
$ hg init
$ echo a > a
Expect exit code 0 on success
$ hg ci -Aqm initial
$ hg co nonexistent
abort: unknown revision 'nonexistent'
[255]
$ hg co 'none()'
abort: empty revision set
[255]
$ hg co 'invalid('
hg: parse error at 8: not a prefix: end
(invalid(
^ here)
[255]
$ hg co 'invalid('
hg: parse error at 8: not a prefix: end
(invalid(
^ here)
[255]
$ hg continue
abort: no operation in progress
[255]
$ hg st --config a=b
abort: malformed --config option: 'a=b' (use --config section.name=value)
[255]
$ echo b > a
$ hg ci -m second
$ echo c > a
$ hg ci -m third
$ hg --config extensions.rebase= rebase -r . -d 0 -q
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
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