HTML escapes left unprocessed

This may belong on https://github.com/pytest-dev/pytest-nunit/ but I'm not sure, so I'll let you move it if necessary :)

My raw rendering of some PyTest output looks like this. The `<` and `>` characters are exactly as displayed.

```
self = <test_raw.TestClass object at 0x04A03B10>, h_cat_rw = 67676864

def test_func_under_test(self, h_cat_rw):
with pytest.raises(ValueError):
> TESTMOD.func_under_test(h_cat_rw, "file.txt", "Tag", uuid.uuid4(), 0, bytes(63))
E Failed: DID NOT RAISE <class 'ValueError'>
```

Start by reproducing the raw-rendering example from the issue and trace where the pytest output is escaped. Done means the rendered output shows angle brackets instead of the literal \u0026lt; and \u0026gt; sequences, with coverage for this example.

Written by the indexing model from the issue text.