improve scaladoc for DoNotInherit (#565)

actor/src/main/java/org/apache/pekko/annotation/DoNotInherit.java

@@ -16,14 +16,14 @@
 import java.lang.annotation.*;
 
 /**
- * Marks APIs that are designed under an closed-world assumption for and are NOT meant to be
- * extended by user-code. It is fine to extend these classes within Apache Pekko itself, however.
+ * Marks APIs that are designed under a closed-world assumption for and are NOT meant to be extended
+ * by user-code. It is fine to extend these classes within Apache Pekko itself, however.
  *
  * <p>This is most useful for binary compatibility purposes when a set of classes and interfaces
  * assume a "closed world" between them, and gain the ability to add methods to the interfaces
  * without breaking binary compatibility for users of this code. Specifically this assumption may be
  * understood intuitively: as all classes that implement this interface are in this compilation unit
- * / artifact, it is impossible to obtain a "old" class with a "new" interface, as they are part of
+ * / artifact, it is impossible to obtain an "old" class with a "new" interface, as they are part of
  * the same dependency.
  *
  * <p>Notable examples of such API include the FlowOps trait in Pekko Streams or Pekko HTTP model