chore(*): add mathlib4 synchronization comments (#19009)
Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status).
Relates to the following files:
* `algebra.category.Group.injective`
* `algebra.category.Ring.basic`
* `algebra.homology.augment`
* `analysis.convex.contractible`
* `analysis.convex.gauge`
* `category_theory.abelian.homology`
* `category_theory.subterminal`
* `model_theory.bundled`
* `model_theory.elementary_maps`
* `model_theory.finitely_generated`
* `model_theory.skolem`
* `topology.category.Top.limits.cofiltered`
* `topology.category.Top.limits.konig`
* `topology.homotopy.contractible`
* `topology.homotopy.path`
* `topology.sheaves.abelian`
