stack: always provide (full) node hash to non-default --template

stack: remove unnecessary prefix from stack output with non-default --template "index" template keyword already exists (the current iteration of the loop), so "stack_index" it is. It follows the same convention as other template keywords, such as "files_added", "line_number", etc.

stack: provide context to formatter with non-default --template This allows using template keywords that we don't explicitly provide to the formatter, e.g. rev, branch and topic.

stack: leverage labelsgen() to produce all needed labels for fm.write()

stack: check if stack is empty more pythonically

stack: implement __bool__ and __nonzero__

stack: get stack data directly from stack and remove stackdata() stackdata function began its life in 137f8b04901e as a proto-stack: it computed stack revs on its own and only had one property to return, "changesetcount". Later it started to prepare and return more properties, but since b933a8068c17 it was computing revs using a getstack function. And then finally in 17749d9d3968 it started to rely on stack class entirely. It was a good function, but now, when all the logic it provided was factored into stack class, I'd say it's finally time for it to be put to rest.

stack: use stack._revs instead of stack.revs[1:] in external children revset The revset in question excludes all revs that are part of the stack. Using stack.revs[1:] works (rev #0 is stack base, which is not a part of the stack), but using stack._revs is technically more correct, because this variable is specifically designed to hold only revisions that are part of the stack.

test: update output to match the parent changesets This amend was forgotten.

topic: add a simple option to reject publishing The option is pretty basic but it can be used as base to build larger feature. The main target for going in this direction is to be able to distinct between user that are "simple contributors" pushing topic for review and the "maintainers" or "automation" that can publish changesets.

compat: adjust `wrapadd` for upstream Mercurial core updated the API in f385ba70e4af.

debian: override default value for SPHINXBUILD in docs/makefile This is the recommended Debian approach. As suggested by Debian Developer Stephen Kitt, use the approach recommended by Debian for building Sphinx documentation. See https://wiki.debian.org/Python/LibraryStyleGuide#Sphinx_documentation Also belated credit to Zash on the #mercurial channel on the Freenode IRC network, who suggested the Make variable approach in the first place.

obshashtree: move obshashtree in its own module The code no longer serve a core purpose. We just keep it because the command might be useful. We move it in a dedicated module so that it does not get in the way of other work.

obsdiscovery: drop `obshash` discovery protocol (issue6136) The protocol has been superseeded by stablerange for a long time. It is untested and more and more buggy. Since this is deprecated experimental code in an experimental code, we drop it. We keep the underlying computation and debug command around for now. They might still be useful to looks at repositories