Adds missing yaml config and fixes missing mvc key.

Fixes spring-cloudgh-3174

Author: spencergibb

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/addrequestheader.adoc

@@ -4,6 +4,20 @@
 The `AddRequestHeader` is a "before" filter that takes a `name` and `value` parameter.
 The following example configures an `AddRequestHeader` filter:
 
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: add_request_header_route
+          uri: https://example.org
+          filters:
+          - AddRequestHeader=X-Request-red, blue
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/addrequestheadersifnotpresent.adoc

@@ -4,6 +4,20 @@
 The `AddRequestHeadersIfNotPresent` filter takes a collection of `name` and `value` pairs separated by colon.
 The following example configures an `AddRequestHeadersIfNotPresent` filter:
 
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: add_request_headers_route
+          uri: https://example.org
+          filters:
+          - AddRequestHeadersIfNotPresent=X-Request-Color-1:blue,X-Request-Color-2:green
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/addrequestparameter.adoc

@@ -4,6 +4,20 @@
 The `AddRequestParameter` Filter takes a `name` and `value` parameter.
 The following example configures an `AddRequestParameter` filter:
 
+application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: add_request_parameter_route
+          uri: https://example.org
+          filters:
+          - AddRequestParameter=red, blue
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/addresponseheader.adoc

@@ -4,6 +4,20 @@
 The `AddResponseHeader` Filter takes a `name` and `value` parameter.
 The following example configures an `AddResponseHeader` filter:
 
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: add_response_header_route
+          uri: https://example.org
+          filters:
+          - AddResponseHeader=X-Response-Red, Blue
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/circuitbreaker-filter.adoc

@@ -13,11 +13,12 @@ The following example configures a Spring Cloud CircuitBreaker  filter:
 spring:
   cloud:
     gateway:
-      routes:
-      - id: circuitbreaker_route
-        uri: https://example.org
-        filters:
-        - CircuitBreaker=myCircuitBreaker
+      mvc:
+        routes:
+        - id: circuitbreaker_route
+          uri: https://example.org
+          filters:
+          - CircuitBreaker=myCircuitBreaker
 ----
 .GatewaySampleApplication.java
 [source,java]
@@ -54,16 +55,17 @@ The following example configures such a fallback:
 spring:
   cloud:
     gateway:
-      routes:
-      - id: circuitbreaker_route
-        uri: https://example.org
-        predicates:
-        - Path=/consumingServiceEndpoint
-        filters:
-        - name: CircuitBreaker
-          args:
-            name: myCircuitBreaker
-            fallbackUri: forward:/inCaseOfFailureUseThis
+      mvc:
+        routes:
+        - id: circuitbreaker_route
+          uri: https://example.org
+          predicates:
+          - Path=/consumingServiceEndpoint
+          filters:
+          - name: CircuitBreaker
+            args:
+              name: myCircuitBreaker
+              fallbackUri: forward:/inCaseOfFailureUseThis
 ----
 
 The following listing does the same thing in Java:
@@ -170,19 +172,20 @@ value or the String representation of the `HttpStatus` enumeration.
 spring:
   cloud:
     gateway:
-      routes:
-      - id: circuitbreaker_route
-        uri: lb://backing-service:8088
-        predicates:
-        - Path=/consumingServiceEndpoint
-        filters:
-        - name: CircuitBreaker
-          args:
-            name: myCircuitBreaker
-            fallbackUri: forward:/inCaseOfFailureUseThis
-            statusCodes:
-              - 500
-              - "NOT_FOUND"
+      mvc:
+        routes:
+        - id: circuitbreaker_route
+          uri: lb://backing-service:8088
+          predicates:
+          - Path=/consumingServiceEndpoint
+          filters:
+          - name: CircuitBreaker
+            args:
+              name: myCircuitBreaker
+              fallbackUri: forward:/inCaseOfFailureUseThis
+              statusCodes:
+                - 500
+                - "NOT_FOUND"
 ----
 
 .GatewaySampleApplication.java

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/deduperesponseheader.adoc

@@ -10,11 +10,12 @@ The following example configures a `DedupeResponseHeader` filter:
 spring:
   cloud:
     gateway:
-      routes:
-      - id: dedupe_response_header_route
-        uri: https://example.org
-        filters:
-        - DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin
+      mvc:
+        routes:
+        - id: dedupe_response_header_route
+          uri: https://example.org
+          filters:
+          - DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin
 ----
 .GatewaySampleApplication.java
 [source,java]

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/fallback-headers.adoc

@@ -9,24 +9,25 @@ The `FallbackHeaders` factory lets you add Spring Cloud CircuitBreaker execution
 spring:
   cloud:
     gateway:
-      routes:
-      - id: ingredients
-        uri: lb://ingredients
-        predicates:
-        - Path=//ingredients/**
-        filters:
-        - name: CircuitBreaker
-          args:
-            name: fetchIngredients
-            fallbackUri: forward:/fallback
-      - id: ingredients-fallback
-        uri: http://localhost:9994
-        predicates:
-        - Path=/fallback
-        filters:
-        - name: FallbackHeaders
-          args:
-            executionExceptionTypeHeaderName: Test-Header
+      mvc:
+        routes:
+        - id: ingredients
+          uri: lb://ingredients
+          predicates:
+          - Path=//ingredients/**
+          filters:
+          - name: CircuitBreaker
+            args:
+              name: fetchIngredients
+              fallbackUri: forward:/fallback
+        - id: ingredients-fallback
+          uri: http://localhost:9994
+          predicates:
+          - Path=/fallback
+          filters:
+          - name: FallbackHeaders
+            args:
+              executionExceptionTypeHeaderName: Test-Header
 ----
 
 .GatewaySampleApplication.java

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/filters/maprequestheader.adoc

@@ -7,6 +7,20 @@ If the input header does not exist, the filter has no impact.
 If the new named header already exists, its values are augmented with the new values.
 The following example configures a `MapRequestHeader`:
 
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: map_request_header_route
+          uri: https://example.org
+          filters:
+          - MapRequestHeader=Blue, X-Request-Red
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----