Add FAPI to IdentityServer overview

Author: maartenba

src/content/docs/identityserver/index.mdx

@@ -41,6 +41,7 @@ Duende IdentityServer supports a wide range of security scenarios for modern app
 - **Audience Constrained Tokens**: Restrict tokens to specific audiences, increasing security in multi-service architectures. Learn more about [audience-constrained tokens](/identityserver/fundamentals/resources/isolation.md).
 - **Sender Constrained Tokens**: Implement Proof of Possession (PoP) tokens with [DPoP or mTLS](/identityserver/tokens/pop.md), which bind tokens to the client, adding another layer of protection.
 - **Pushed Authorization Requests (PAR)**: Support [Pushed Authorization Requests](/identityserver/tokens/par.md) to enhance the security of the authorization flow.
+- **FAPI 2.0**: protect APIs in high-value scenarios with the[FAPI 2.0 Security profile](/identityserver/tokens/fapi-2-0-specification.md).
 
 ## Licensing