No pretty failure message for in statements

[JoshKarpel]

Working on tests for #233 and noticed that in statements don't seem to be getting rewritten to produce pretty output. Minimal example:

@test("assert in not working?")
def _():
    assert "foo" in "bar"

─────────────────────────────────────────────── assert in not working? ───────────────────────────────────────────────

  Failed at tests/test_terminal.py:300

      298 @test("assert in not working?")
      299 def _():
    ❱ 300     assert "foo" in "bar"
      301

──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

[darrenburns]

We only print pretty output for the == operator:

ward/ward/_terminal.py

Line 683 in 3bc5de8

if err.operator == Comparison.Equals:

If we wanted to print special output for the in case, we could add it to the above block of code.

It's not as clear what we'd print in that case, since a diff won't make sense for anything other than equality checks.

[JoshKarpel]

Ah, gotcha... I will see if I can come up with anything nice :)