contrib: make merge-test-compat.sh more topic-friendly

contrib: shellcheck merge-test-compat.sh

evolve: add pre-check logic for content-divergence in rewriteutil.precheck() For now, pre-check will abort if rewriting a rev create divergence (and config experimental.evolution.allowdivergence is not set to True). But this behaviour can be improved where instead of abort maybe we can confirm the user to either proceed with divergence or some other options depends on what command user is running. Changes in test file are used to overrides the pre-check for testing purpose (using experimental.evolution.allowdivergence=yes).

evolve: rename a function to make it explicit

obsdiscovery: compatibility when importing forcebytestr()

heptapod-ci: add pytype job, allow it to fail for now

evolve: add a new method picksplitsuccessor() in utility.py This patch adds the logic to return a single successor of a rev which was split. If split revisions are on a single topological branch then we return highest one; otherwise prompt user to choose an evolve destination.

changelog: add missing entries

compat: also import datestr from dateutil

obshistory: remove unused ismetablacklisted() Code that used this function was removed in 461b9a91b662. But we still need to add one item currently missing from METABLACKLIST in core: touch noise.