Standardize nominative reporters regex group names

[grossir]

The citations from these reporters may not have a volume, which may make them overlap with full case citations. For example: "Ellenburg v. Chase, 2004 MT 66", where a candidate nominative reporter citation is "Chase 2004", while "2004 MT 66" is the correct but overlapped full citation.

By standardizing their named groups, we may handle the error above easily; as well as store them as citations when they do happen. Currently, the Courtlistener Citation and UnmatchedCitation models do not accept null volumes, so correct nominative citations like "In the case of The Indiana, Crabbe, 479, repairs were furnished in Philadelphia..." will me marked as errors

Check parent and sibling issues for more examples and use cases