chore(*): add mathlib4 synchronization comments (#19215)
Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status).
Relates to the following files:
* `field_theory.abel_ruffini`
* `geometry.manifold.algebra.lie_group`
* `geometry.manifold.algebra.monoid`
* `geometry.manifold.algebra.structures`
* `geometry.manifold.bump_function`
* `geometry.manifold.cont_mdiff`
* `geometry.manifold.cont_mdiff_map`
* `geometry.manifold.vector_bundle.basic`
* `geometry.manifold.vector_bundle.fiberwise_linear`
* `geometry.manifold.vector_bundle.pullback`
* `geometry.manifold.vector_bundle.tangent`
* `linear_algebra.clifford_algebra.equivs`
* `linear_algebra.clifford_algebra.fold`
* `number_theory.class_number.finite`
* `number_theory.class_number.function_field`
* `number_theory.cyclotomic.gal`
* `number_theory.cyclotomic.rat`
* `number_theory.number_field.class_number`
* `representation_theory.group_cohomology.resolution`
* `topology.metric_space.dilation`
