sparse: refactor activeprofiles into a generic function (API) activeprofiles() is a special case of a more generic function. Furthermore, that generic function is essentially already implemented inline in the sparse extension. So, refactor activeprofiles() to a generic activeconfig(). Change the only consumer of activeprofiles() to use it. And have the inline implementation in the sparse extension use it.

check-code: prohibit `if False` antipattern Differential Revision: https://phab.mercurial-scm.org/D20

convert: remove `if False` block This code has never run since its introduction on July 18th, 2007. It's time for it to go. Differential Revision: https://phab.mercurial-scm.org/D19

filterpyflakes: move self-test into test file This will avoid a false positive on an upcoming check-code rule. Differential Revision: https://phab.mercurial-scm.org/D18

test-subrepo: demonstrate a status problem when merge deletes a file At the interactive update prompt, if (c) is chosen and then followed by `hg rm`, both `status -R` and `status -S` show the file as 'R', and `files -R` shows no files (OK, because explicitly removed files aren't supposed to be listed). If `rm` follows selecting (c), then both flavors of `status` list the file as '!', and `files -R` lists the missing file. So somehow, the (d) option has followed a third path.

subrepo: make the output references to subrepositories consistent Well, mostly. The annotation on subrepo functions tacks on a parenthetical to the abort message, which seems reasonable for a generic mechanism. But now all messages consistently spell out 'subrepository', and double quote the name of the repo. I noticed the inconsistency in the change for the last commit.