Update python library DocStrings

src/descriptor_identifier/Model/Model.hpp

src/descriptor_identifier/Model/ModelClassifier.hpp

src/descriptor_identifier/Model/ModelLogRegressor.hpp

src/descriptor_identifier/Model/ModelRegressor.hpp

src/descriptor_identifier/SISSO_DI/SISSOClassifier.hpp

src/descriptor_identifier/SISSO_DI/SISSOLogRegressor.hpp

src/descriptor_identifier/SISSO_DI/SISSORegressor.hpp

src/feature_creation/feature_space/FeatureSpace.hpp

src/feature_creation/node/FeatureNode.hpp

src/feature_creation/node/ModelNode.hpp

src/feature_creation/node/Node.hpp

src/feature_creation/node/operator_nodes/OperatorNode.hpp

...rator_nodes/allowed_operator_nodes/abs/absolute_value.hpp

...lowed_operator_nodes/abs/parameterized_absolute_value.hpp

...s/allowed_operator_nodes/abs_diff/absolute_difference.hpp

...ator_nodes/abs_diff/parameterized_absolute_difference.hpp

...on/node/operator_nodes/allowed_operator_nodes/add/add.hpp

...or_nodes/allowed_operator_nodes/add/parameterized_add.hpp

...on/node/operator_nodes/allowed_operator_nodes/cb/cube.hpp

...or_nodes/allowed_operator_nodes/cb/parameterized_cube.hpp