Rename spring.favicon.enabled property

Rename `spring.favicon.enabled` to `spring.mvc.favicon.enabled`.

See gh-2377

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration.java

@@ -288,7 +288,7 @@ public class WebMvcAutoConfiguration {
 		}
 
 		@Configuration
-		@ConditionalOnProperty(value = "spring.favicon.enabled", matchIfMissing = true)
+		@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
 		public static class FaviconConfiguration implements ResourceLoaderAware {
 
 			private ResourceLoader resourceLoader;

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfigurationTests.java

@@ -374,7 +374,8 @@ public class WebMvcAutoConfigurationTests {
 		this.context.register(Config.class, WebMvcAutoConfiguration.class,
 				HttpMessageConvertersAutoConfiguration.class,
 				PropertyPlaceholderAutoConfiguration.class);
-		EnvironmentTestUtils.addEnvironment(this.context, "spring.favicon.enabled:false");
+		EnvironmentTestUtils.addEnvironment(this.context,
+				"spring.mvc.favicon.enabled:false");
 		this.context.refresh();
 		assertThat(
 				this.context.getBeansOfType(ResourceHttpRequestHandler.class).get(

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -92,11 +92,11 @@ content into your application; rather pick only the properties that you need.
 	# SPRING MVC ({sc-spring-boot-autoconfigure}/web/WebMvcProperties.{sc-ext}[WebMvcProperties])
 	spring.mvc.locale= # set fixed locale, e.g. en_UK
 	spring.mvc.date-format= # set fixed date format, e.g. dd/MM/yyyy
+	spring.mvc.favicon.enabled=true
 	spring.mvc.message-codes-resolver-format= # PREFIX_ERROR_CODE / POSTFIX_ERROR_CODE
 	spring.mvc.ignore-default-model-on-redirect=true # If the the content of the "default" model should be ignored redirects
 	spring.view.prefix= # MVC view prefix
 	spring.view.suffix= # ... and suffix
-	spring.favicon.enabled=true
 
 	# SPRING RESOURCES HANDLING ({sc-spring-boot-autoconfigure}/web/ResourceProperties.{sc-ext}[ResourceProperties])
 	spring.resources.cache-period= # cache timeouts in headers sent to browser