mathlib3

e04043d6 - chore(*): add mathlib4 synchronization comments (#18196)

chore(*): add mathlib4 synchronization comments (#18196) Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status). Relates to the following files: * `algebra.gcd_monoid.multiset` * `algebra.hom.group_action` * `algebra.order.smul` * `data.finset.basic` * `data.finset.card` * `data.finset.fin` * `data.finset.fold` * `data.finset.image` * `data.finset.option` * `data.finset.order` * `data.finset.pi` * `data.finset.prod` * `data.finset.sum` * `data.fintype.basic` * `data.fintype.pi` * `data.int.succ_pred` * `data.multiset.antidiagonal` * `data.set.constructions` * `data.set.intervals.iso_Ioo`