mathlib

c34a1aa4 - feat(data/list/join): add `list.append_join_append` and `list.reverse_join` (#17554)

feat(data/list/join): add `list.append_join_append` and `list.reverse_join` (#17554) Co-authored-by: madvorak <dvorakmartinbridge@seznam.cz> Co-authored-by: Martin Dvořák <dvorakmartinbridge@seznam.cz>