MNT: Fix types in interpolate docstring.
MNT: Fix types in interpolate docstring.

dopplershift/MetPy,ShawnMurd/MetPy,jrleeman/MetPy,ahaberlie/MetPy,dopplershift/MetPy,ahill818/MetPy,ahaberlie/MetPy,Unidata/MetPy,jrleeman/MetPy,Unidata/MetPy