content_type added as kwarg but generates as positional parameter

[kristapratico]

PR for reference: #1167

The kwarg shows up in the docstring, but then gets generated as a positional parameter in the generated method call:

This can be repro'd using the swagger README for text analytics here: https://github.com/Azure/azure-sdk-for-python/tree/main/sdk/textanalytics/azure-ai-textanalytics/swagger

[catalinaperalta]

Context:
Using @autorest/python@5.15.0 and @autorest/modelerfour@4.19.1. Past versions don't resolve this either.

Can repro using the swagger README here.

Issue:
Adding some other content-type issues recently found when generating with the Form Recognizer swagger for the 2022-05-31-preview (this version adds many more supported content-types):

• Same issue as mentioned above with content-type being added as a positional parameter in the generated method call.
• For the FR generation, it is also showing up twice in the method signature in _operations_mixin.py:
  
  (along the same line, the docs are also duplicated) My observation is that it seems that one instance of content type allows str or ~azure.ai.formrecognizer.v2022_05_31_preview.models.ContentType while the other only allows str.
• Same issue is happening in operations/_form_recognizer_client_operations.py in _analyze_document_initial:
  
• Same issue also in the same file as the previous point, in begin_analyze_document:
  

These issues affect both sync and async, looks like the FR issues are probably all related to the same underlying cause.