sklearn/linear_model/_stochastic_gradient.py

Ref #22115

I do not anticipate negative power_t to be mathematically meaningful but apparently our code accepts it without crashing... So ok with documenting it.

Originally posted by @ogrisel in #22115 (comment)

@thomasjpfan

I feel like this a case where documenting -inf will lead to more people trying out. If this is not mathematically meaningful, then we could be promoting a bad practice?

cc: @glemaitre