Fix grammar mistake in reference documentation.

See #2487.

Author: gregturn

README.adoc

@@ -3,8 +3,8 @@ image:https://spring.io/badges/spring-data-jpa/snapshot.svg[Spring Data JPA,link
 
 = Spring Data JPA image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-jpa%2Fmain&subject=Build[link=https://jenkins.spring.io/view/SpringData/job/spring-data-jpa/] https://gitter.im/spring-projects/spring-data[image:https://badges.gitter.im/spring-projects/spring-data.svg[Gitter]]
 
-Spring Data JPA, part of the larger https://projects.spring.io/spring-data[Spring Data] family, makes it easy to easily implement JPA based repositories.
-This module deals with enhanced support for JPA based data access layers.
+Spring Data JPA, part of the larger https://projects.spring.io/spring-data[Spring Data] family, makes it easy to implement JPA-based repositories.
+This module deals with enhanced support for JPA-based data access layers.
 It makes it easier to build Spring-powered applications that use data access technologies.
 
 Implementing a data access layer of an application has been cumbersome for quite a while.