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

diff --cc fetch-pack.c
Simple merge