Document Saved Requests

Closes gh-12088

docs/modules/ROOT/partials/servlet/architecture/request-cache-continue.adoc

@@ -0,0 +1,50 @@
+.`RequestCache` Only Checks for Saved Requests if `continue` Parameter Present
+====
+.Java
+[source,java,role="primary"]
+----
+@Bean
+DefaultSecurityFilterChain springSecurity(HttpSecurity http) throws Exception {
+	HttpSessionRequestCache requestCache = new HttpSessionRequestCache();
+	requestCache.setMatchingRequestParameterName("continue");
+	http
+		// ...
+		.requestCache((cache) -> cache
+			.requestCache(requestCache)
+		);
+	return http.build();
+}
+----
+
+.Kotlin
+[source,kotlin,role="secondary"]
+----
+@EnableWebSecurity
+class SecurityConfig {
+
+	@Bean
+	open fun springSecurity(http: HttpSecurity): SecurityFilterChain {
+		val httpRequestCache = HttpSessionRequestCache()
+		httpRequestCache.setMatchingRequestParameterName("continue")
+		http {
+			requestCache {
+				requestCache = httpRequestCache
+			}
+		}
+		return http.build()
+	}
+}
+----
+
+.XML
+[source,xml,role="secondary"]
+----
+<http auto-config="true">
+	<!-- ... -->
+	<request-cache ref="requestCache"/>
+</http>
+
+<b:bean id="requestCache" class="org.springframework.security.web.savedrequest.HttpSessionRequestCache"
+	p:matchingRequestParameterName="continue"/>
+----
+====