Inferred new includeStaticFiles in documentation

Added the `includeStaticFiles` parameter in the `MapTopicErrors()` example, and annotated it with a note in the corresponding comment. This isn't very explicit documentation, but helps indicate that this functionality exists.

Author: JeremyCaney

OnTopic.AspNetCore.Mvc/README.md

@@ -187,7 +187,7 @@ public class Startup {
   public void Configure(IApplicationBuilder app, IWebHostEnvironment env) {
     app.UseEndpoints(endpoints => {
       endpoints.MapTopicErrors();                        // Error/{errorCode}
-      endpoints.MapTopicErrors("Errors");                // Errors/{errorCode}
+      endpoints.MapTopicErrors("Errors", false);         // Errors/{errorCode}; disables includeStaticFiles
       endpoints.MapDefaultControllerRoute();             // Error/Http/{errorCode}
       endpoints.MapTopicRoute("Error");                  // Error/{path}; e.g., Error/Unauthorized
     }