rebase: improve help text
- add a paragraph about default dest/source changesets
- option help: say "changeset" not "revision"
- option help: explain -b/--base better
- clarify that -a/--abort and -c/--continue are different from the
other options
adding a
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
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adding a
created new head
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
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0 files updated, 0 files merged, 1 files removed, 0 files unresolved
marked working directory as branch testing
% should not issue warning