Refer to Datastore everywhere correctly by its capitalized form

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=147479683

java/google/registry/model/annotations/NotBackedUp.java

@@ -22,7 +22,7 @@ import java.lang.annotation.Target;
 
 /**
  * Annotation for an Objectify {@link Entity} to indicate that it should not be backed up by the
- * default datastore backup configuration (it may be backed up by something else).
+ * default Datastore backup configuration (it may be backed up by something else).
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)