Document just-in-time methods for handles
Summary: Fixes T7689. I'm not going to go clean up all the rest of the loadViewerHandles() calls right now since a lot of them are kind of a pain and they aren't really hurting anything so it doesn't feel very leveraged, but at least deprecate it and document the new hotness.
have a look
in a book
Reviewed By: btrahan
Maniphest Tasks: T7689
Differential Revision: https://secure.phabricator.com/D12343