[Python] 5094 followup - Reduce redundancy in docs (#5161)

* Reduce redundancy in python docs

This is a followup to PR #5094, which had a few unresolved comments at
merge time. This reduces the amount of redundant lines in the api
example doc templates, and ensures that referenced Configuration objects
are actually instantiated.

* Regenerate samples

samples/client/petstore/python-tornado/docs/FakeApi.md

@@ -482,6 +482,7 @@ configuration.password = 'YOUR_PASSWORD'
 
 # Defining host is optional and default to http://petstore.swagger.io:80/v2
 configuration.host = "http://petstore.swagger.io:80/v2"
+
 # Enter a context with an instance of the API client
 with petstore_api.ApiClient(configuration) as api_client:
     # Create an instance of the API class