Rollup merge of #97389 - m-ou-se:memory-ordering-diagnostics, r=estebank
Improve memory ordering diagnostics
Before:

After:

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Before this change, the compiler suggests the failure ordering is too strong and suggests choosing a weaker ordering. After this change, it instead suggests the success ordering is not strong enough, and suggests chosing a stronger one. This is more likely to be correct.
Also, before this change, the compiler suggested downgrading an invalid AcqRel failure ordering to Relaxed, without mentioning Acquire as an option.