mathlib3

1a7fb7e4 - feat(data/list/sort): add sorted.rel_of_mem_take_of_mem_drop (#6027)

feat(data/list/sort): add sorted.rel_of_mem_take_of_mem_drop (#6027) Also renames the existing lemmas to enable dot notation Co-authored-by: pechersky@users.noreply.github.com