chore: minor typo fix (#609)

Author: aditya-arolkar-swe

fern/products/sdks/overview/python/configuration.mdx

@@ -20,7 +20,7 @@ groups:
             - from: file_with_custom_function
               imports:
                 - custom_function
-          pydantic-config:
+          pydantic_config:
             skip_validation: true
 ```
 
@@ -192,13 +192,13 @@ When enabled, includes the API name as part of the package structure and naming.
   The name of the exported client class that will be used in code snippets.
 </ParamField>
 
-### pydantic-config
+### pydantic_config
 
 Configure Pydantic model generation settings for your Python SDK.
 
 ```yaml
 config:
-  pydantic-config:
+  pydantic_config:
     enum_type: "literals"
     extra_fields: "forbid"
     frozen: true