Update asp0018.md (#31168)

aspnetcore/diagnostics/asp0018.md

@@ -21,7 +21,7 @@ A route parameter is specified but not used.
 
 ## Rule description
 
-A route parameter is specified but not used. In the example below, the `name` parameter is defined in the route but not in the route handler.
+A route parameter is specified but not used. In the example below, the `id` parameter is defined in the route but not in the route handler.
 
 ```csharp
 var app = WebApplication.Create();
@@ -32,6 +32,11 @@ app.MapGet("/{id}", () => ...);
 ## How to fix violations
 
 To fix a violation of this rule, remove the route parameter or add code that uses the parameter.
+```csharp
+var app = WebApplication.Create();
+
+app.MapGet("/{id}", (id) => ...);
+```
 
 ## When to suppress warnings