reference updates

[n-kall]

Summary

Adjust citation for nested R-hat to published version and fix references to parts of the paper. Also fixes a typo in the journal name for the rank normalized R-hat paper.

Copyright and Licensing

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license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

[paul-buerkner]

Thanks!