mathlib

ef377a92 - chore(data/list/sort): docs, add a few lemmas (#5274)

chore(data/list/sort): docs, add a few lemmas (#5274) * Add a module docstring and section headers. * Rename `list.eq_of_sorted_of_perm` to `list.eq_of_perm_of_sorted`; the new name reflects the order of arguments. * Add a few lemmas.