Fix copy-and-paste error in docs

src/docs/asciidoc/web/webmvc.adoc

@@ -1292,13 +1292,13 @@ a proxy at the boundary of trust should be configured to remove untrusted `Forwa
 headers that come from the outside. You can also configure the `ForwardedHeaderFilter`
 with `removeOnly=true`, in which case it removes but does not use the headers.
 
-In order to support <<mvc-ann-async,asynchronous requests>> this filter must be mapped
-with `DispatcherType.ASYNC` so that the filter can delay and successfully generate the an
-ETag to the end of the last async dispatch. If using Spring Framework's
-`AbstractAnnotationConfigDispatcherServletInitializer` (see <<mvc-container-config>>)
-all filters are automatically registered for all dispatch types. However if registering
-the filter via web.xml or in Spring Boot via a `FilterRegistrationBean` be sure to include
-`DispatcherType.ASYNC`.
+In order to support <<mvc-ann-async,asynchronous requests>> and error dispatches this
+filter should be mapped with `DispatcherType.ASYNC` and also `DispatcherType.ERROR`.
+If using Spring Framework's `AbstractAnnotationConfigDispatcherServletInitializer`
+(see <<mvc-container-config>>) all filters are automatically registered for all dispatch
+types. However if registering the filter via web.xml or in Spring Boot via a
+`FilterRegistrationBean` be sure to include `DispatcherType.ASYNC` and
+`DispatcherType.ERROR` in addition to `DispatcherType.REQUEST`.