Commit 2024-10-16 08:50 4564def3

chore(Multiset/Basic): added gcongr and congr to Multiset (#17793) While working on some theorems about MvPolynomial.degrees, I noticed that a lot of Multiset functions do not have gcongr or congr attributes. So I added them in this PR. Note: I only looked at the definitions in Multiset/Basic. If this PR is approved I will do the same for other functions in Multiset folder.