Add citation for random.orthogonal.

[carlosgmartin]

https://github.com/google/jax/pull/23207#discussion_r1731137697

[mattjj]

Just curious, why this reference and not e.g. one of the others from https://nhigham.com/2020/04/22/what-is-a-random-orthogonal-matrix/?

[carlosgmartin]

Stewart (1980) and Anderson et al. (1987) use a different technique. Mezzadri (2007) is this reference. Higham (2002) and Edelman and Rao (2005) seem to be more general references on the subjects of numerical algorithms and random matrix theory, respectively.

[carlosgmartin]

@dfm