Tracking issue for RFC 2451, "Re-Rebalancing Coherence"

[Centril]

This is a tracking issue for the RFC "Re-Rebalancing Coherence" (rust-lang/rfcs#2451).

Steps:

• Implement the RFC – Implement the Re-rebalance coherence RFC #56145
• Adjust documentation (see instructions on forge)
• Stabilization proposal
• Stabilization PR (see instructions on forge)

Unresolved questions:

• Are there additional implementations which are clearly acceptable under the current restrictions, which are disallowed with this extension? Should we allow them if so?

[dwijnand]

Implemented in #56145.

[weiznich]

To just add a implementation example:
We've used this feature to improve the implementation of diesel-oci. For this use case it seems to work fine.

@Centril Somebody needs to update the boxes in the opening comment and change the label to B-RFC-implemented.