chore(*): add mathlib4 synchronization comments (#18450)
Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status).
Relates to the following files:
* `category_theory.arrow`
* `category_theory.balanced`
* `category_theory.category.preorder`
* `category_theory.endomorphism`
* `category_theory.epi_mono`
* `category_theory.functor.currying`
* `category_theory.functor.hom`
* `category_theory.groupoid`
* `category_theory.groupoid.basic`
* `category_theory.pi.basic`
* `category_theory.types`
* `computability.DFA`
* `computability.language`
* `computability.turing_machine`
* `data.fintype.card_embedding`
* `group_theory.commensurable`
* `order.filter.germ`
* `set_theory.ordinal.arithmetic`
* `topology.algebra.group_with_zero`
* `topology.list`
