Polish

Closes gh-11145

README.adoc

@@ -204,7 +204,7 @@ can also watch files, automatically recompiling and restarting when they change.
 === spring-boot-actuator
 Spring Boot Actuator provides additional auto-configuration to decorate your application
 with features that make it instantly deployable and supportable in production.  For
-instance if you are writing a JSON web service then it will provide a server, security,
+instance, if you are writing a JSON web service then it will provide a server, security,
 logging, externalized configuration, management endpoints, an audit abstraction, and
 more. If you want to switch off the built in features, or extend or replace them, it
 makes that really easy as well.