[docs] quant_kwargs

[stevhliu]

Improves where you can find the quant_kwargs in the PipelineQuantizationConfig docs

[sayakpaul]

Thanks! Do we have to include an explicit point on how users can derive qaunt_kwargs for a given backend?

[asomoza]

I'm undecided as to what is best, to include each quantization backend here as @sayakpaul mentioned or to an index of them like you did, so I'll leave it to you.

Also I wanted to see the final docs but the doc builder failed.