largest-series-product: add hint to @Ignore annotations

exercises/largest-series-product/src/test/java/LargestSeriesProductCalculatorTest.java

         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLengthTwoWithNumbersNotInOrder() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("576802143");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductWhenSeriesLengthEqualsStringToSearchLength() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("29");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLengthThreeWithNumbersInOrder() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("0123456789");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLengthThreeWithNumbersNotInOrder() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("1027839564");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLengthFiveWithNumbersInOrder() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("0123456789");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductInLongStringToSearchV1() {
         final LargestSeriesProductCalculator calculator
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductInLongStringToSearchV2() {
         final LargestSeriesProductCalculator calculator
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductInLongStringToSearchFromProjectEuler() {
         final LargestSeriesProductCalculator calculator
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfZeroIfAllDigitsAreZeroes() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("0000");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfZeroIfAllSeriesOfGivenLengthContainZero() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("99099");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testSeriesLengthLongerThanLengthOfStringToTestIsRejected() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("123");
         calculator.calculateLargestProductForSeriesLength(4);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLength0ForEmptyStringToSearch() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testCorrectlyCalculatesLargestProductOfLength0ForNonEmptyStringToSearch() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("123");
         assertEquals(expectedProduct, actualProduct);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testEmptyStringToSearchAndSeriesOfNonZeroLengthIsRejected() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("");
         calculator.calculateLargestProductForSeriesLength(1);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testStringToSearchContainingNonDigitCharacterIsRejected() {
         expectedException.expect(IllegalArgumentException.class);
         new LargestSeriesProductCalculator("1234a5");
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testNegativeSeriesLengthIsRejected() {
         final LargestSeriesProductCalculator calculator = new LargestSeriesProductCalculator("12345");
         calculator.calculateLargestProductForSeriesLength(-1);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testNullStringToSearchIsRejected() {
         expectedException.expect(IllegalArgumentException.class);