mathlib3

e7161393 - feat(algebra/homology/Module): API for complexes of modules (#12622)

feat(algebra/homology/Module): API for complexes of modules (#12622) API for homological complexes in `Module R`. Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Kevin Buzzard <k.buzzard@imperial.ac.uk>