mathlib3

d774ef68 - feat(topology/path_connected): add lemmas about paths and continuous families of paths (#4063)

feat(topology/path_connected): add lemmas about paths and continuous families of paths (#4063) From the sphere eversion project (see https://github.com/leanprover-community/sphere-eversion/pull/12) Co-authored-by: Anatole <anatolededecker@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Anatole Dedecker <48656793+ADedecker@users.noreply.github.com>