Auto merge of #115412 - eswartz:docs/total_cmp-test-result-in-docs, r=scottmcm

Expose tests for {f32,f64}.total_cmp in docs

Expose tests for {f32,f64}.total_cmp in docs

Uncomment the helpful `assert_eq!` line, which is stripped out completely in docs, and leaves the reader to mentally play through the algorithm, or go to the playground and add a println!, to see what the result will be.

(If these tests are known to fail on some platforms, is there some mechanism to conditionalize this or escape the test so the `assert_eq!` source will be visible on the web? I am a newbie, which is why I was reading docs ;)

Author: bors