fix: change name from histogram to frequency

Author: Alex Klymenko

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

@@ -28,11 +28,11 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
      */
     @Override
     public <T extends Comparable<T>> List<T> sort(List<T> list) {
-        Map<T, Integer> frequencyMap = computeHistogramMap(list);
-        return formSortedArrayFromHistogramMap(list, frequencyMap);
+        Map<T, Integer> frequencyMap = computeFequencyMap(list);
+        return formSortedArrayFromFrequencyMap(list, frequencyMap);
     }
 
-    private static <T extends Comparable<T>> List<T> formSortedArrayFromHistogramMap(List<T> list, Map<T, Integer> frequencyMap) {
+    private static <T extends Comparable<T>> List<T> formSortedArrayFromFrequencyMap(List<T> list, Map<T, Integer> frequencyMap) {
         List<T> sortedList = new ArrayList<>(list.size());
         for (Map.Entry<T, Integer> entry : frequencyMap.entrySet()) {
             for (int i = 0; i < entry.getValue(); i++) {
@@ -42,7 +42,7 @@ private static <T extends Comparable<T>> List<T> formSortedArrayFromHistogramMap
         return sortedList;
     }
 
-    private static <T extends Comparable<T>> Map<T, Integer> computeHistogramMap(List<T> list) {
+    private static <T extends Comparable<T>> Map<T, Integer> computeFequencyMap(List<T> list) {
         // TreeMap to maintain order of elements naturally.
         Map<T, Integer> frequencyMap = new TreeMap<>();
         for (T element : list) {