Failling unit-to-str test

[neutrinoceros]

Bug report

this bug was apparently introduced with the merging of. #2437

This possibly belongs in unyt

code for reproduction

pytest yt/visualization/tests/test_plotwindow.py::test_set_unit

actual outcome

========================================= FAILURES ==========================================
_______________________________________ test_set_unit _______________________________________

    def test_set_unit():
        ds = fake_random_ds(32, fields=('temperature',), units=('K',))
        slc = SlicePlot(ds, 2, 'temperature')

        orig_array = slc.frb['gas', 'temperature'].copy()

        slc.set_unit('temperature', 'degF')

>       assert str(slc.frb['gas', 'temperature'].units) == '°F'
E       AssertionError: assert 'degF' == '°F'
E         - °F
E         + degF

yt/visualization/tests/test_plotwindow.py:478: AssertionError

versions:
yt: master (b6d9463)
unyt: 2.7.1

[neutrinoceros]

I believe this was resolved with the release of unyt 2.7.2.