Fix Reactive OAuth2 Kotlin DSL examples

Closes gh-10580

docs/modules/ROOT/pages/reactive/oauth2/client/authorization-grants.adoc

@@ -162,7 +162,7 @@ class SecurityConfig {
 
     @Bean
     fun securityFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             authorizeExchange {
                 authorize(anyExchange, authenticated)
             }
@@ -170,8 +170,6 @@ class SecurityConfig {
                 authorizationRequestResolver = authorizationRequestResolver(customClientRegistrationRepository)
             }
         }
-
-        return http.build()
     }
 
     private fun authorizationRequestResolver(
@@ -282,13 +280,11 @@ class OAuth2ClientSecurityConfig {
 
     @Bean
     fun securityFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Client {
                 authorizationRequestRepository = authorizationRequestRepository()
             }
         }
-
-        return http.build()
     }
 }
 ----
@@ -363,13 +359,11 @@ class OAuth2ClientSecurityConfig {
 
     @Bean
     fun securityFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Client {
                 authenticationManager = authorizationCodeAuthenticationManager()
             }
         }
-
-        return http.build()
     }
 
     private fun authorizationCodeAuthenticationManager(): ReactiveAuthenticationManager {

docs/modules/ROOT/pages/reactive/oauth2/client/index.adoc

@@ -55,7 +55,7 @@ class OAuth2ClientSecurityConfig {
 
     @Bean
     fun securityFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Client {
                 clientRegistrationRepository = clientRegistrationRepository()
                 authorizedClientRepository = authorizedClientRepository()
@@ -64,8 +64,6 @@ class OAuth2ClientSecurityConfig {
                 authenticationManager = authenticationManager()
             }
         }
-
-        return http.build()
     }
 }
 ----

docs/modules/ROOT/pages/reactive/oauth2/login/advanced.adoc

@@ -60,7 +60,7 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login {
                 authenticationConverter = authenticationConverter()
                 authenticationMatcher = authenticationMatcher()
@@ -75,8 +75,6 @@ class OAuth2LoginSecurityConfig {
                 securityContextRepository = securityContextRepository()
             }
         }
-
-        return http.build()
     }
 }
 ----
@@ -158,7 +156,7 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             exceptionHandling {
                 authenticationEntryPoint = RedirectServerAuthenticationEntryPoint("/login/oauth2")
             }
@@ -166,8 +164,6 @@ class OAuth2LoginSecurityConfig {
                 authorizationRequestResolver = authorizationRequestResolver()
             }
         }
-
-        return http.build()
     }
 
     private fun authorizationRequestResolver(): ServerOAuth2AuthorizationRequestResolver {
@@ -243,13 +239,11 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login {
                 authenticationMatcher = PathPatternParserServerWebExchangeMatcher("/login/oauth2/callback/{registrationId}")
             }
         }
-
-        return http.build()
     }
 }
 ----
@@ -369,11 +363,9 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean
@@ -458,11 +450,9 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean
@@ -536,11 +526,9 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean
@@ -594,11 +582,9 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean
@@ -730,7 +716,7 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             authorizeExchange {
                 authorize(anyExchange, authenticated)
             }
@@ -739,8 +725,6 @@ class OAuth2LoginSecurityConfig {
                 logoutSuccessHandler = oidcLogoutSuccessHandler()
             }
         }
-
-        return http.build()
     }
 
     private fun oidcLogoutSuccessHandler(): ServerLogoutSuccessHandler {

docs/modules/ROOT/pages/reactive/oauth2/login/core.adoc

@@ -341,14 +341,12 @@ class OAuth2LoginSecurityConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             authorizeExchange {
                 authorize(anyExchange, authenticated)
             }
             oauth2Login { }
         }
-
-        return http.build()
     }
 }
 ----
@@ -411,14 +409,12 @@ class OAuth2LoginConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             authorizeExchange {
                 authorize(anyExchange, authenticated)
             }
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean
@@ -505,14 +501,12 @@ class OAuth2LoginConfig {
 
     @Bean
     fun securityWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
-        http {
+        return http {
             authorizeExchange {
                 authorize(anyExchange, authenticated)
             }
             oauth2Login { }
         }
-
-        return http.build()
     }
 
     @Bean