Merge pull request #63 from lightningdevkit/TheBlueMatt-patch-2

Make filter initialization compile

Author: valentinewallace

docs/build_node_rust.md

@@ -209,8 +209,8 @@ let filter = YourTxFilter();
 **Example:**
 
 ```rust
-let filter: Option<Filter> = // leave this as None or insert the Filter trait
-                             // object, depending on what you did for Step 5
+let filter: Option<Box<dyn Filter>> = // leave this as None or insert the Filter trait
+                                      // object, depending on what you did for Step 5
 
 let chain_monitor = ChainMonitor::new(
     filter, &broadcaster, &logger, &fee_estimator, &persister