Parameter missing from docs - overwrite parameter & description of behavior missing

Parameter missing from docs - overwrite parameter & description of behavior missing from docstring for FileDatasetFactory.upload_directory

What should I expect if overwrite = True? Overwrite the whole directory, or just duplicate files?
Does the method raise if overwrite is false and a duplicate is found?

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#### Document Details

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* ID: 091afd7e-72ca-a384-01db-4da4d40a6734
* Version Independent ID: 0f3783bf-ab1f-f0d6-08f3-90becae914e8
* Content: [azureml.data.dataset_factory.FileDatasetFactory class - Azure Machine Learning Python](https://docs.microsoft.com/en-us/python/api/azureml-core/azureml.data.dataset_factory.filedatasetfactory?view=azure-ml-py#from-files-path--validate-true--partition-format-none--is-file-false-)
* Content Source: [AzureML-Docset/stable/docs-ref-autogen/azureml-core/azureml.data.dataset_factory.FileDatasetFactory.yml](https://github.com/MicrosoftDocs/MachineLearning-Python-pr/blob/live/AzureML-Docset/stable/docs-ref-autogen/azureml-core/azureml.data.dataset_factory.FileDatasetFactory.yml)
* Service: **machine-learning**
* Sub-service: **core**
* GitHub Login: @DebFro
* Microsoft Alias: **debfro**

Start with the linked FileDatasetFactory reference and the AzureML-Docset/stable/docs-ref-autogen/azureml-core/azureml.data.dataset_factory.FileDatasetFactory.yml source. Check the upload_directory API behavior for overwrite=True and duplicate files when overwrite=False, then update the missing parameter description and expected behavior in the documentation.

Written by the indexing model from the issue text.