rebase: switch ui.log calls to common style The old style raised errors in some cases. Differential Revision: https://phab.mercurial-scm.org/D1748

hgweb: link to successors of obsoleted changesets _siblings() prepare various useful properties to use in templates. This function usually prepares parents and children of changesets for use in hgweb templates, but it can be used for successors too. It's needed because item['successors'] is a _hybrid object that works well when used in regular templates, but in hgweb templates work slightly differently and can't get hex nodes of the successors, which are required for these links to work.

hgweb: display fate of obsolete changesets Operations that obsolete changesets store enough metadata to explain what happened after the fact. One way to get that metadata is showsuccsandmarkers function, which returns a list of successors of a particular changeset and appropriate obsolescence markers. Templates have a set of experimental functions that have names starting with obsfate. This patch uses some of these functions to interpret output of succsandmarkers() and produce human-friendly messages that describe what happened to an obsolete changeset, e.g. "pruned" or "rewritten as 6:3de5eca88c00". In commonentry(), succsandmarkers property is made callable so it's only executed on demand; this saves time when changeset is not obsolete, and also in e.g. /shortlog view, where there are a lot of changesets, but we don't need to show each and every one in detail. In spartan theme, succsandmarkers is used instead of the simple "obsolete: yes", in other themes a new line is added to /rev page.