style: enable MultipleVariableDeclarations in checkstyle (#5175)

Co-authored-by: vaibhav <vaibhav.waghmare@techprescient.com>

src/main/java/com/thealgorithms/conversions/DecimalToOctal.java

@@ -18,7 +18,11 @@ public final class DecimalToOctal {
     // enter in a decimal value to get Octal output
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
-        int n, k, d, s = 0, c = 0;
+        int n;
+        int k;
+        int d;
+        int s = 0;
+        int c = 0;
         System.out.print("Decimal number: ");
         n = sc.nextInt();
         k = n;