chore(*): add mathlib4 synchronization comments (#19055)
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.projective`
* `algebra.monoid_algebra.to_direct_sum`
* `analysis.convex.strict_convex_space`
* `analysis.convex.uniform`
* `analysis.normed_space.banach`
* `analysis.normed_space.bounded_linear_maps`
* `analysis.normed_space.complemented`
* `analysis.normed_space.finite_dimension`
* `analysis.normed_space.mazur_ulam`
* `analysis.special_functions.log.base`
* `analysis.special_functions.log.monotone`
* `analysis.special_functions.pow.real`
* `combinatorics.additive.salem_spencer`
* `data.is_R_or_C.lemmas`
* `linear_algebra.adic_completion`
* `linear_algebra.cross_product`
* `measure_theory.measure.doubling`
* `ring_theory.graded_algebra.basic`
* `ring_theory.mv_polynomial.homogeneous`
* `ring_theory.valuation.extend_to_localization`
* `topology.algebra.module.star`
