templater: set the correct phase for parents
Akin to f6371cc62d2a which did this for `hg log`, the following sets
the correct phase for the {phase} keyword when the context is a parent
of the current cset. This allows templates such as the following to be
defined,
parent = '{label("log.parent changeset.{phase}",
"parent: {rev}:{node|formatnode}")}\n'
which when called on a parent (e.g. with the `parents` template
keyword), will produce the correct phase.
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Ran 16 tests in 0.000s
OK