Fix clang-format: add final newlines to DoubleHashingSort files

- Add required newline at end of DoubleHashingSort.java
- Add required newline at end of DoubleHashingSortTest.java
- Ensures clang-format compliance with EOF newline requirement
- Files now end properly with newline character as expected

Author: PauLopNun

src/main/java/com/thealgorithms/sorts/DoubleHashingSort.java

@@ -95,4 +95,4 @@ private <T extends Comparable<T>> int getBucketIndex(T element, int bucketCount)
         // For simplicity, we use i = 1 here, but could be extended for collision resolution
         return (hash1 + hash2) % bucketCount;
     }
-}
+}

src/test/java/com/thealgorithms/sorts/DoubleHashingSortTest.java

@@ -9,4 +9,4 @@ public class DoubleHashingSortTest extends SortingAlgorithmTest {
     SortAlgorithm getSortAlgorithm() {
         return new DoubleHashingSort();
     }
-}
+}