bash/zsh completion: use HGPLAIN when invoking hg (issue2297)

patch: fix extract() docstring, it returns branch as well

merge with stable

doc: remove has_key usage in hgmanpage

gendoc: remove callable usage (check-code)

bookmarks: rewrite _bookmarks method documentation

init: create target directory recursively Subrepos with relative paths must often be cloned to locations deep in the directory structure. This allows clone over ssh (init+push) work.

doc: make sure we use our own code for generating man pages docutils would in some situations pick up its own manpage.py instead of doc/manpage.py. Renaming to hgmanpage.py makes it less ambiguous.