webutil: make _siblings into an object with __iter__ and __len__
_siblings is a helper that is used for displaying changeset parents and
children in hgweb. Before, when it was a simple generator, it couldn't tell its
length without being consumed, and that required a special case when preparing
data for changeset template (see
9e1f4c65f5f5).
Let's make it into a class (similar to templatekw._hybrid) that allows len(...)
without side-effects.
mergestate: move binary format documentation into _readrecordsv2
This is too low-level to be the top-level documentation for mergestate. We're
restricting the top-level documentation to only be about what consumers of the
mergestate and anyone extending it need to care about.
unshelve: add support for custom merge tools
For parity with merge --tool, rebase --tool etc.
rebase.rebase overwrites the tool in repo.ui, so we need to explicitly pass it
down there too.
unshelve: add -k as short form of --keep
For parity with strip -k, rebase -k, etc.
import-checker: allow symbol imports from hgweb.common and .request
This seems the convention of hgweb.