docs: improve map_add_ons method documentation (#20248)

Author: hawkadrian

crates/node/builder/src/builder/mod.rs

@@ -533,6 +533,27 @@ where
     }
 
     /// Modifies the addons with the given closure.
+    ///
+    /// This method provides access to methods on the addons type that don't have
+    /// direct builder methods. It's useful for advanced configuration scenarios
+    /// where you need to call addon-specific methods.
+    ///
+    /// # Examples
+    ///
+    /// ```rust,ignore
+    /// use tower::layer::util::Identity;
+    ///
+    /// let builder = NodeBuilder::new(config)
+    ///     .with_types::<EthereumNode>()
+    ///     .with_components(EthereumNode::components())
+    ///     .with_add_ons(EthereumAddOns::default())
+    ///     .map_add_ons(|addons| addons.with_rpc_middleware(Identity::default()));
+    /// ```
+    ///
+    /// # See also
+    ///
+    /// - [`NodeAddOns`] trait for available addon types
+    /// - [`crate::NodeBuilderWithComponents::extend_rpc_modules`] for RPC module configuration
     pub fn map_add_ons<F>(self, f: F) -> Self
     where
         F: FnOnce(AO) -> AO,
@@ -579,10 +600,10 @@ where
     ///     .extend_rpc_modules(|ctx| {
     ///         // Access node components, so they can used by the CustomApi
     ///         let pool = ctx.pool().clone();
-    ///         
+    ///
     ///         // Add custom RPC namespace
     ///         ctx.modules.merge_configured(CustomApi { pool }.into_rpc())?;
-    ///         
+    ///
     ///         Ok(())
     ///     })
     ///     .build()?;

crates/node/builder/src/builder/states.rs

@@ -235,6 +235,27 @@ where
     }
 
     /// Modifies the addons with the given closure.
+    ///
+    /// This method provides access to methods on the addons type that don't have
+    /// direct builder methods. It's useful for advanced configuration scenarios
+    /// where you need to call addon-specific methods.
+    ///
+    /// # Examples
+    ///
+    /// ```rust,ignore
+    /// use tower::layer::util::Identity;
+    ///
+    /// let builder = NodeBuilder::new(config)
+    ///     .with_types::<EthereumNode>()
+    ///     .with_components(EthereumNode::components())
+    ///     .with_add_ons(EthereumAddOns::default())
+    ///     .map_add_ons(|addons| addons.with_rpc_middleware(Identity::default()));
+    /// ```
+    ///
+    /// # See also
+    ///
+    /// - [`NodeAddOns`] trait for available addon types
+    /// - [`crate::NodeBuilderWithComponents::extend_rpc_modules`] for RPC module configuration
     pub fn map_add_ons<F>(mut self, f: F) -> Self
     where
         F: FnOnce(AO) -> AO,