Update reference documentation for JSONP support

Issue: SPR-12113

Author: sdeleuze

src/asciidoc/index.adoc

@@ -1063,7 +1063,8 @@ method has been added.
   summary vs. detail page). This is also supported with View-based rendering by
   adding the serialization view type as a model attribute under a special key.
   See <<mvc-ann-jsonview>> for details.
-* JSONP is now supported with Jackson.
+* JSONP is now supported with Jackson, both for <<mvc-ann-jsonp,response body methods>> and
+  <<view-json-mapping,`View`-based rendering>>.
 * A new lifecycle option is available for intercepting `@ResponseBody` and `ResponseEntity`
   methods just after the controller method returns and before the response is written.
   To take advantage declare an `@ControllerAdvice` bean that implements `ResponseBodyAdvice`.
@@ -31710,8 +31711,26 @@ to the model:
 			return "userView";
 		}
 	}
+----
+
+[[mvc-ann-jsonp]]
+===== Jackson JSONP Support
+
+In order to enable http://en.wikipedia.org/wiki/JSONP[JSONP] support for your response
+body methods, declare an `@ControllerAdvice` as shown below:
 
+[source,java,indent=0]
+[subs="verbatim,quotes"]
 ----
+	@ControllerAdvice
+	public class JsonpAdvice extends AbstractJsonpResponseBodyAdvice {
+
+		public JsonpAdvice() {
+			super("callback");
+		}
+	}
+----
+
 
 [[mvc-ann-async]]
 ==== Asynchronous Request Processing
@@ -37004,6 +37023,10 @@ annotations. When further control is needed, a custom `ObjectMapper` can be inje
 through the `ObjectMapper` property for cases where custom JSON
 serializers/deserializers need to be provided for specific types.
 
+http://en.wikipedia.org/wiki/JSONP[JSONP] is supported and automatically enabled when
+the request has a query parameter named `jsonp` or `callback`. The JSONP query parameter
+name(s) could be customized thanks to the `JsonpParameterNames` property.
+