Fix broken link to default-values extension page (#5195)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: github-actions[bot]

fern/products/sdks/deep-dives/generated-sdk.mdx

@@ -49,7 +49,7 @@ When you define webhooks in your API spec, Fern automatically [generates utiliti
 
 ## Default parameter values
 
-You can configure [default values](/learn/api-definitions/openapi/extensions/default) for path, header, and query parameters, including headers defined under [`x-fern-global-headers`](/learn/api-definitions/openapi/extensions/global-headers). The SDK makes those parameters optional and sends the default when the caller doesn't provide one — useful for things like pinning an API version header or default region. Supported in TypeScript, Python, Go, Java, C#, PHP, and Ruby SDKs.
+You can configure [default values](/learn/api-definitions/openapi/extensions/default-values) for path, header, and query parameters, including headers defined under [`x-fern-global-headers`](/learn/api-definitions/openapi/extensions/global-headers). The SDK makes those parameters optional and sends the default when the caller doesn't provide one — useful for things like pinning an API version header or default region. Supported in TypeScript, Python, Go, Java, C#, PHP, and Ruby SDKs.
 
 ## Customization options