Update What's New for 5.8

Issue gh-11952

docs/modules/ROOT/pages/whats-new.adoc

@@ -13,3 +13,4 @@ Below are the highlights of the release.
 * https://github.com/spring-projects/spring-security/pull/11908[gh-11908] - Make X-Xss-Protection header value configurable in ServerHttpSecurity
 * https://github.com/spring-projects/spring-security/issues/11347[gh-11347] - Simplify Java Configuration `RequestMatcher` Usage
 * https://github.com/spring-projects/spring-security/issues/9159[gh-9159] - Add `securityMatcher` as an alias on `requestMatcher` in `HttpSecurity`
+* https://github.com/spring-projects/spring-security/issues/11952[gh-11952] - Add `csrfTokenRequestResolver` to `CsrfDsl`