remotenames: don't inherit the remotenames class from dict class The remotenames class was moved from hgremotenames extension. The class in hgremotenames extension used to extend dict because updating bookmark was done through a dict-like interface or Sean (smf) wanted it to be that way. But now, we can remove the inheritance from the dict class as updating bookmark is not done using a dict-like interface. Thanks to Martin von Zweigbergk for spotting this. Differential Revision: https://phab.mercurial-scm.org/D2361