Add missing Rust card to generators.yml config reference (#4206)

Co-authored-by: fern-support <support@buildwithfern.com>
Co-authored-by: bot_apk <apk@cognition.ai>

Author: 3 people

fern/products/sdks/reference/generators-yml-reference.mdx

@@ -554,6 +554,8 @@ groups:
 </Card>
 <Card title="Swift" href="/sdks/generators/swift/configuration">
 </Card>
+<Card title="Rust" href="/sdks/generators/rust/configuration">
+</Card>
 </CardGroup>