Merge pull request #10411 from dreis2211:typo-external-config-docs

* pr/10411:
  Typo in external config documentation

Author: snicoll

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

@@ -980,7 +980,7 @@ does not inject other beans from the context. Having said that, The
 `@EnableConfigurationProperties` annotation is _also_ automatically applied to your project
 so that any _existing_ bean annotated with `@ConfigurationProperties` will be configured
 from the `Environment`. You could shortcut `MyConfiguration` above by making sure
-`FooProperties` is a already a bean:
+`FooProperties` is already a bean:
 
 [source,java,indent=0]
 ----