[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/openapi3/client/petstore/python/docs/PetApi.md

@@ -35,6 +35,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -94,6 +95,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -157,6 +159,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -220,6 +223,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -285,6 +289,7 @@ configuration.api_key['api_key'] = 'YOUR_API_KEY'
 
 # 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
@@ -347,6 +352,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -408,6 +414,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -471,6 +478,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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
@@ -535,6 +543,7 @@ configuration.access_token = 'YOUR_ACCESS_TOKEN'
 
 # 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