PintArray formatting broken for degC

[MichaelTiemannOSC]

Dataframes of temperatures print nicely. PintArrays do not. Consider this code condensed from TestIssue21 of the Pint-Pandas testsuite (migrated from https://github.com/hgrecco/pint/issues/812)

import numpy as np
import pandas as pd

from pint_pandas import PintArray, PintType

ureg = PintType.ureg

q_a = ureg.Quantity(np.arange(5), ureg.Unit("degC"))

q_a = ureg.Quantity(np.arange(5)+ufloat(0,0.1), ureg.Unit("degC"))
q_b = ureg.Quantity(np.arange(6)+ufloat(0,0.1), ureg.Unit("degC"))
q_a_ = np.append(q_a, ufloat(np.nan, 0))

a = pd.Series(PintArray(q_a))
b = pd.Series(PintArray(q_b))

result = pd.concat([a, b], axis=1)

We can print q_a and a, but not PintArray(q_a) when units are degC. We can print all three when units are m.

The offender is the getitem method of PintArray, here:

        if is_integer(item):
            return self._data[item] * self.units # Should not use multiplication to create a quantity from magnitude and unit