Merge branch 'ka/want-ref-in-namespace' into maint

"git upload-pack" which runs on the other side of "git fetch" forgot to take the ref namespaces into account when handling want-ref requests. * ka/want-ref-in-namespace: docs: clarify the interaction of transfer.hideRefs and namespaces upload-pack.c: treat want-ref relative to namespace t5730: introduce fetch command helper