SMOTEN does not support sparse matricies

[o-parry]

SMOTEN does not support sparse matrices in fit and fit_resample despite the documentation indicating that it does.

imbalanced-learn/imblearn/over_sampling/_smote/base.py

Line 831 in 64fc1ca

accept_sparse=False,

[glemaitre]

Thanks for reporting. Indeed, we should update the documentation.
A PR would be welcome to solve this issue.