add boolean Page.hasNextPage()

so that iteration works via page.hasNextPage() instead
of more verbosely page.nextPageRequest() != null

api/src/main/java/jakarta/data/page/Page.java

@@ -41,6 +41,13 @@
  */
 public interface Page<T> extends Slice<T> {
 
+    /**
+     * Returns {@code true} if it is known that there are more results, so that
+     * {@link #nextPageRequest()} will definitely not return {@code null}.
+     * @return {@code false} if this the last page of results
+     */
+    boolean hasNextPage();
+
     /**
      * Returns the total number of elements across all pages that can be requested for the query.
      * @return the total number of elements across all pages.

api/src/main/java/jakarta/data/page/impl/PageRecord.java

@@ -55,6 +55,11 @@ public int numberOfElements() {
         return content.size();
     }
 
+    @Override
+    public boolean hasNextPage() {
+        return moreResults;
+    }
+
     @Override
     @SuppressWarnings("unchecked")
     public <E> PageRequest<E> pageRequest(Class<E> entityClass) {