remotenames: introduce new template keywords for remotenames
This patch introduces three new template keywords 'remotenames',
'remotebookmarks', 'remotebranches' to show remotenames, remotebookmarks and
remotebranches associated to a changeset.
This is a part of moving hgremotenames extension to core. The remotenames
template keyword was present in the extension and the rest of the two are not
present in the hgremotenames extension and are introduced in this patch.
hgremotenames: https://bitbucket.org/seanfarley/hgremotenames
Differential Revision: https://phab.mercurial-scm.org/D1759
#require docutils gettext
$ $TESTDIR/check-gendoc fr
checking for parse errors