Merge branch 'ps/odb-drop-whence' into next

The 'whence' field in 'struct object_info' has been removed, refactoring backend-specific object information retrieval into an opt- in 'struct object_info_source' structure. * ps/odb-drop-whence: odb: document object info fields odb: drop `whence` field from object info treewide: convert users of `whence` to the new source field odb: add `source` field to struct object_info_source odb: make backend-specific fields optional packfile: thread odb_source_packed through packed_object_info()