Fix documentation code block bug

Fixes #12850

docs/modules/ROOT/pages/servlet/authentication/session-management.adoc

@@ -243,7 +243,7 @@ public void login(@RequestBody LoginRequest loginRequest, HttpServletRequest req
     Authentication authentication = authenticationManager.authenticate(token); <4>
     SecurityContext context = securityContextHolderStrategy.createEmptyContext();
     context.setAuthentication(authentication); <5>
-    securityContextHolderStrategy.setContext(authentication);
+    securityContextHolderStrategy.setContext(context);
     securityContextRepository.saveContext(context, request, response); <6>
 }
 
@@ -911,7 +911,7 @@ public class SomeClass {
         // ...
         SecurityContext context = this.securityContextHolderStrategy.createEmptyContext(); <1>
         context.setAuthentication(authentication); <2>
-        this.securityContextHolderStrategy.setContext(authentication); <3>
+        this.securityContextHolderStrategy.setContext(context); <3>
     }
 
 }