run-tests: remove obsolete coverage check and packaging import (issue6805) This removes an obsolete `coverage` version check (version from a decade ago). This also conveniently removes the dependency over `packaging.version`, which requires some additional installation since Python 3.10.

test-tx-rollback: more lenient glob for kill status (issue6807) The "killed" message may have some prefix and/or suffix which differ depending on the platform. This makes the pinned test output more lenient to accept those.

commands: correct documentation of hg serve’s --ipv6 option When the --ipv6 option is given, the server doesn’t listen to a IPv4 socket. This can be verified by running two servers, one with and one without the option, which works fine. I think that listening to both a IPv4 and a IPv6 socket would be better, but given that the Python standard library class underlying the HTTP server supports only one socket, this is not trivial.

rhg: don't crash on empty directory names in path_encode, just in case I don't expect that to be possible, but there's nothing in path_encode.rs that prevents it, and the old code didn't crash in this case, so it's better to be defensive.