pythagorean-triplet : add hint to @Ignore annotations

#473

exercises/pythagorean-triplet/src/test/java/PythagoreanTripletTest.java

     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void shouldCalculateProduct() {
         PythagoreanTriplet sut = new PythagoreanTriplet(3, 4, 5);
         final long expected = 60l;
     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void testIsPythagoreanOK() {
         PythagoreanTriplet sut = new PythagoreanTriplet(3, 4, 5);
         assertTrue(sut.isPythagorean());
     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void testIsPythagoreanFail() {
         PythagoreanTriplet sut = new PythagoreanTriplet(5, 6, 7);
         assertFalse(sut.isPythagorean());
     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void shouldMakeTripletsUpToTen() {
         final List<Long> actual
                 = PythagoreanTriplet
     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void shouldMakeTripletsElevenToTwenty() {
         final List<Long> actual
                 = PythagoreanTriplet
     }
 
     @Test
-    @Ignore
+    @Ignore("Remove to run test")
     public void shouldMakeTripletsAndFilterOnSum() {
         final List<Long> actual
                 = PythagoreanTriplet