How to use state to set <joint>'s initial position?

https://osrf-migration.github.io/sdformat-gh-pages/#!/osrf/sdformat/pull-requests/683/page/1

This comment says that initial position is better suited for the state tag. How do we do this?

Start with the linked migration page and its comment about using the state tag for a joint's initial position. Determine the supported SDFormat usage for setting this position and document a clear example; done means the question is answered with enough detail for users to apply it.

Written by the indexing model from the issue text.