Introduce @AutoConfigureTestRestTemplate

Add `@AutoConfigureTestRestTemplate` which can be used to
auto-configure a `TestRestTemplate`.

See gh-46356

Author: wilkinsona

documentation/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/utilities/testresttemplate/MySpringBootTests.java

@@ -23,6 +23,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.restclient.test.TestRestTemplate;
+import org.springframework.boot.restclient.test.autoconfigure.AutoConfigureTestRestTemplate;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.boot.test.context.TestConfiguration;
@@ -32,6 +33,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+@AutoConfigureTestRestTemplate
 class MySpringBootTests {
 
 	@Autowired

documentation/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/utilities/testresttemplate/MySpringBootTests.kt

@@ -24,10 +24,12 @@ import org.springframework.boot.test.context.SpringBootTest.WebEnvironment
 import org.springframework.boot.test.context.TestConfiguration
 import org.springframework.boot.restclient.RestTemplateBuilder
 import org.springframework.boot.restclient.test.TestRestTemplate
+import org.springframework.boot.restclient.test.autoconfigure.AutoConfigureTestRestTemplate
 import org.springframework.context.annotation.Bean
 import java.time.Duration
 
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+@AutoConfigureTestRestTemplate
 class MySpringBootTests(@Autowired val template: TestRestTemplate) {
 
 	@Test