docs(SortArgs) - Fix bug in ExerciseRunner (#2138)

Restores the default `System.out` to fix result printing

`System.out` was changed to a custom `printStream`, so `System.out.println(output.equals("1 2 3 4\n"));` printed `true` or `false` to this `printStream` and not the default `System.out`. This causes console output to be empty.

subjects/java/piscine/SortArgs/README.md

@@ -28,8 +28,13 @@ public class ExerciseRunner {
     public static void main(String[] args) throws IOException {
         ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
         PrintStream printStream = new PrintStream(outputStream);
+
+        var defaultOut = System.out;
+
         System.setOut(printStream);
         SortArgs.sort(new String[]{"4", "2", "1", "3"});
+        System.setOut(defaultOut);
+
         String output = outputStream.toString();
         System.out.println(output.equals("1 2 3 4\n"));
     }