1st line of the math.perm docstring doesn't mention a default value for k

Here is an example how this looks in the IDLE:
![1](https://user-images.githubusercontent.com/2155800/215657351-fae17dec-a5b2-40f3-b599-bfb606060f51.png)

While full docstring and the sphinx docs looks fine, the first line doesn't describe the function signature correctly.

_Originally posted by @skirpichev in https://github.com/python/cpython/issues/89381#issuecomment-1409708287_