chore(undergrad.yaml): updates (#4160)
Added a bunch of things to `undergrad.yaml`: generalized eigenspaces, conjugacy classes in a group, the orthogonal complement, continuity of monotone functions and their inverses, inverse hyperbolic trig functions, radius of convergence. Also changed (hopefully improved) some translations.
Co-authored-by: Rob Lewis <rob.y.lewis@gmail.com>
Co-authored-by: Patrick Massot <patrickmassot@free.fr>
