Polish "Fix default strategy description of ProblemDetail error codes"

See gh-32446

Author: snicoll

framework-docs/modules/ROOT/pages/web/webmvc/mvc-ann-rest-exceptions.adoc

@@ -74,13 +74,16 @@ It is a common requirement to customize and internationalize error response deta
 It is also good practice to customize the problem details for Spring MVC exceptions
 to avoid revealing implementation details. This section describes the support for that.
 
-An `ErrorResponse` exposes message codes for "type" and "title". `ResponseEntityExceptionHandler` resolves
+An `ErrorResponse` exposes message codes for "type", "title", and "detail", as well as
+message code arguments for the "detail" field. `ResponseEntityExceptionHandler` resolves
 these through a xref:core/beans/context-introduction.adoc#context-functionality-messagesource[MessageSource]
 and updates the corresponding `ProblemDetail` fields accordingly.
 
-The default strategy for message codes follows the pattern:
+The default strategy for message codes is as follows:
 
-`problemDetail.[type|title].[fully qualified exception class name]`
+* "type": `problemDetail.type.[fully qualified exception class name]`
+* "title": `problemDetail.title.[fully qualified exception class name]`
+* "detail": `problemDetail.[fully qualified exception class name][suffix]`
 
 An `ErrorResponse` may expose more than one message code, typically adding a suffix
 to the default message code. The table below lists message codes, and arguments for