neg combinator results in unhelpful failure logging

[craigfe]

The neg : 'a testable -> 'a testable combinator inverts the meaning of equality used for testing, but doesn't signal this to the printing logic in any way. This can produce some confusing output:

Alcotest.(check @@ neg int) "" 1 1

File "tests/main.ml", line 25, character 21:

   Expected: `1'
   Received: `1'

[ethanuppal]

Any update on this?