chore(*): add mathlib4 synchronization comments (#18807)
Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status).
Relates to the following files:
* `algebra.category.Module.epi_mono`
* `algebraic_topology.split_simplicial_object`
* `analysis.asymptotics.specific_asymptotics`
* `analysis.asymptotics.superpolynomial_decay`
* `analysis.asymptotics.theta`
* `analysis.box_integral.box.basic`
* `analysis.locally_convex.balanced_core_hull`
* `analysis.normed_space.extr`
* `category_theory.limits.over`
* `category_theory.sites.sheafification`
* `linear_algebra.free_module.rank`
* `order.filter.zero_and_bounded_at_filter`
* `topology.category.Top.epi_mono`
