Merge pull request #5159 from carltongibson/docs/get_schema_view_params

Add `generator_class` parameter to `get_schema_view` docs.

docs/api-guide/schemas.md

@@ -188,6 +188,12 @@ to be exposed in the schema:
         patterns=schema_url_patterns,
     )
 
+#### `generator_class`
+
+May be used to specify a `SchemaGenerator` subclass to be passed to the
+`SchemaView`.
+
+
 
 ## Using an explicit schema view