Fix typo

See gh-12996

Author: snicoll

spring-boot-docs/src/main/asciidoc/using-spring-boot.adoc

@@ -615,7 +615,7 @@ as `final`, indicating that it cannot be subsequently changed.
 == Using the @SpringBootApplication annotation
 Many Spring Boot developers like their apps to use auto-configuration, component scan and
 be able to define extra configuration on their "application class". A single
-`@SpringBootApplication` annotation can be used to enable those tree features, that is:
+`@SpringBootApplication` annotation can be used to enable those three features, that is:
 
 * `@EnableAutoConfiguration`: enable <<using-boot-auto-configuration,Spring Boot's
 auto-configuration mechanism>>