shelve: drop mention of obsshelve file Core shelve extension does not use obsolescence, we clean up this unused file before adding a new info file.

shelve: rename method for data write/read There are no user of this code nor any code related to obsshelve in the extensions right now, so we rename the function before using them. Note: The shelvedfile looks a bit strange. We should probably refactor it, however, this is an adventure for another series.

shelve: move createcmd next to _docreatecmd It is simpler not to have to jump around the file all the time.

minirst: filter blocks by full path to section

minirst: mark getsections() as an internal helper

help: rewrite parsing of help topic to not drop section name with dots A subtopic is no longer lowercased since it should be considered a part of a topic path, not a section filter.

test-help: add tests showing that sections can't be filtered by dotted name

revlogdeltas: move finddeltainfo filtering inside _candidategroups Now all "simple" filtering logic is gathered in one place. The `finddeltainfo` method is more straightforward and the `_candidate_groups` function knows more about filtering revisions before we compute a delta against them.

revlogdeltas: split candidate groups selection from the filtering logic The group iteration has two main components: * walking candidates, the logic that we are about to extend to build intermediate snapshots, * Making sure we test diffs against interesting bases. No duplicated tests, skipping empty revisions, etc. We split `_candidategroups` to separate the two components. This achieves two goals: * It will be simpler to update the walking logic for intermediate snapshots, * We can gather the filtering logic from `finddeltainfo` into `_candidategroups` to centralize it.

revlogdeltas: pass revision number to _candidatesgroups The `_candidates_groups` logic works on revisions, so the nodes are currently just converted to revs at the top of the function. It seems cleaner to instead pass revision numbers to the function. Having this conversion out of the way will help for further cleanups.