0**-oo produces 0, the documentation says it should produce zoo

[arnog]

Using SymPy 1.5.1, evaluate 0**-oo produces 0.

The documentation for the Pow class states that it should return ComplexInfinity, aka zoo

expr	value	reason
0**-oo	zoo	This is not strictly true, as 0**oo may be oscillating between positive and negative values or rotating in the complex plane. It is convenient, however, when the base is positive.