mathlib

2ec920d3 - feat(data/list/lemmas): add lemmas about `set.range list.nth*` (#18647)

feat(data/list/lemmas): add lemmas about `set.range list.nth*` (#18647) Add versions for `list.nth_le`, `list.nth`, `list.nthd`, and `list.inth`. Also move lemmas from `list` to `set` namespace.