Skip to definition of python unary operators when in python-mode.

[Hongyi Zhao]

Say, if I put the point on the following position denoted by `|' when
I'm in python-mode:

a = ~|4

I want to be directed to the definition of unary-arithmetic operators
as documented here [1]. Any hints for achieving this behavior?

[1] 
https://docs.python.org/3/reference/expressions.html#unary-arithmetic-and-bitwise-operations

Regards, HZ