PolynomialFeatures' docstring does not mention that sparse data is allowed for fit #16646
Description
Describe the issue linked to the documentation
The docs for PolynomialFeatures.fit() does not mention that sparse data is allowed. The same holds true for fit_transform.
Suggest a potential alternative/fix
The docs for PolynomialFeatures.fit() and PolynomialFeatures.fit_transform() mention that sparse data is allowed.