📝 fix docs

We are simplifying our graph convolution models by a joint data representation (:code:`GraphData`)

in a future version of DeepChem, so we provide several featurizers.

:code:`ConvMolFeaturizer` and :code:`WeaveFeaturizer` are used with graph convolution models

which inherited :code:`KerasModel`. On the other hand, :code:`MolGraphConvFeaturizer` is used

with graph convolution models which inherited :code;`TorchModel`.

:code:`ConvMolFeaturizer` and :code:`WeaveFeaturizer` are used

with graph convolution models  which inherited :code:`KerasModel`.

:code:`ConvMolFeaturizer` is used with graph convolution models

except :code:`WeaveModel`. :code:`WeaveFeaturizer` are only used with :code:`WeaveModel`.

On the other hand, :code:`MolGraphConvFeaturizer` is used

with graph convolution models which inherited :code:`TorchModel`.

ConvMolFeaturizer

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