errors: move UnknownCommand and AmbiguousCommand near CommandError
They seem closely related.
Differential Revision: https://phab.mercurial-scm.org/D9163
templatekw: make {successorssets} always return a list (
issue6342)
Previously, {successorssets} returns an empty string instead of an empty list
for a non-obsolete changeset. The changing type of the JSON output makes it
hard to consume from statically-typed languages.
Differential Revision: https://phab.mercurial-scm.org/D9158
tests: test output of {predecessors}, {successorssets} for non-obsolete csets
Differential Revision: https://phab.mercurial-scm.org/D9157