Merge branch 'jt/fetch-pack-loosen-validation-with-packfile-uri'

Bugfix for "git fetch" when the packfile URI capability is in use. * jt/fetch-pack-loosen-validation-with-packfile-uri: fetch-pack: make packfile URIs work with transfer.fsckobjects fetch-pack: document only_packfile in get_pack() (various): document from_promisor parameter