Add documentation to B_MaxSalaryInEachDept.java

Author: ZahidFKhan

src/test/java/com/github/streams/interview/problems/employee/D_NumberOfEmployeeInEachDept.java

@@ -7,6 +7,26 @@
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
+/**
+ * Calculation of the number of employees in each department. <br>
+ *
+ * <pre>
+ * Input:
+ * Employee("John", "Sales", 50000)
+ * Employee("Jane", "Marketing", 60000)
+ * Employee("Bob", "Sales", 70000)
+ *
+ * Output:
+ * {
+ * "Sales": 2,
+ * "Marketing": 1
+ * }
+ * </pre>
+ *
+ * Explanation: This method takes a list of employees as input, groups them by their department
+ * names, and returns a map where the keys are the department names and the values are the number of
+ * employees in each department.
+ */
 class D_NumberOfEmployeeInEachDept {
   @Test
   @Disabled