text: Title: docs: parameter and return types
  Body: @Fix types in docstrings under:
  
  Parameters
  ------------
  
  Returns
  --------
  
  to utilize our new auto-typing where possible:  https://github.com/cleanlab/cleanlab/pull/412 
  
  Sphinx can now automatically insert the type for us in the docstring (based on type annotation in the function signature), so you should not specify the type of Parameter or Return-variable *unless* it is a custom/nonstandard type that looks ugly when automatically inserted by Sphinx (this is only referring to the docstring, you still always have to specify type in function signature where you define what args it takes).  The best strategy would be to remove all the type annotations (only in docstrings, not function signatures!) in a file and rebuild the docs to see how it looks. Then add back the subset of types that were not properly auto-inserted by Sphinx or simply don't look good.  
  
  This has already been done for files in token_classification module, which you can reference.
  Remaining files to do/verify this for:
  
  - [ ] classification.py
  - [ ] count.py
  - [ ] dataset.py
  - [ ] filter.py
  - [ ] multiannotator.py
  - [ ] outlier.py
  - [ ] rank.py
  - [ ] experimental/keras.py
  - [ ] experimental/fasttext.py
  - [ ] experimental/coteaching.py
  - [ ] experimental/mnist_pytorch.py
  - [ ] experimental/cifar_cnn.py
  - [ ] internal/label_quality_utils.py
  - [ ] internal/latent_algebra.py
  - [ ] internal/token_classification_utils.py
  - [ ] internal/util.py
  - [ ] internal/validation.py
  - [ ] benchmarking/noise_generation.py