mathlib

cce7f68a - feat(algebra/module/composition_series): Jordan-Hölder for modules (#17295)

feat(algebra/module/composition_series): Jordan-Hölder for modules (#17295) Co-authored-by: D.M.H. van Gent <gentdmhvan@u0031838.vuw.leidenuniv.nl> Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>