asymmetry requirements in PartialOrd

[VitalyAnkh]

In the blog post tour of rust standard library traits, I feel the paragraph of asymmetry requirements in partial_cmp is not right:

All PartialOrd impls must ensure that comparisons are asymmetric and transitive. That means for all a, b, and c:

• a < b implies !(a > b) (asymmetry)
• a < b && b < c implies a < c (transitivity)

In the document for PartialOrd, there is no part about asymmetry. The requirements for partial_cmp is:

The comparison must satisfy, for all a, b and c:

• transitivity: a < b and b < c implies a < c. The same must hold for both == and >.
• duality: a < b if and only if b > a.

Maybe the document is updated and we should catch up?