Add documentation for 'subset' and interpolation' arguments (ImageDataGenerator) (#9817)
Add documentation for 'subset' and interpolation' arguments (ImageDataGenerator) (#9817)

* Add documentation for 'subset' argument (flow and flow_from_directory) and for 'interpolation' argument (flow_from_directory)

* Fix style for 'flow' and 'flow_from_directory' ImageDataGenerator methods doc

keras-team/keras,keras-team/keras