chore(*): add mathlib4 synchronization comments (#17871)
Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status).
Relates to the following PRs:
* `algebra.group.ulift`: https://github.com/leanprover-community/mathlib4/pull/906
* `algebra.group.with_one.basic`: https://github.com/leanprover-community/mathlib4/pull/922
* `algebra.group_with_zero.units.lemmas`: https://github.com/leanprover-community/mathlib4/pull/920
* `algebra.order.field.defs`: https://github.com/leanprover-community/mathlib4/pull/905
* `algebra.order.group.abs`: https://github.com/leanprover-community/mathlib4/pull/896
* `algebra.order.group.inj_surj`: https://github.com/leanprover-community/mathlib4/pull/916
* `algebra.order.group.type_tags`: https://github.com/leanprover-community/mathlib4/pull/921
* `algebra.order.monoid.with_top`: https://github.com/leanprover-community/mathlib4/pull/902
* `algebra.order.positive.ring`: https://github.com/leanprover-community/mathlib4/pull/911
* `algebra.order.ring.canonical`: https://github.com/leanprover-community/mathlib4/pull/905
* `algebra.order.ring.char_zero`: https://github.com/leanprover-community/mathlib4/pull/905
* `algebra.order.ring.defs`: https://github.com/leanprover-community/mathlib4/pull/905
* `algebra.order.ring.inj_surj`: https://github.com/leanprover-community/mathlib4/pull/917
* `algebra.ring.idempotents`: https://github.com/leanprover-community/mathlib4/pull/918
