DOC: removed hypen to fix docs build numpydoc warnings
I noticed a few warning in a recent PR. This should fix them. 

Ref:
![Screenshot of docs build warning in CI](https://user-images.githubusercontent.com/6564007/213683432-7a79a34d-4c84-4e52-896a-5e8b73d5af6c.png)

![Screenshot of detailed numpydoc warnings](https://user-images.githubusercontent.com/6564007/213683456-5a01914a-858e-497e-88ea-158a520d48e5.png)

Thanks @noatamir 