pangram: rename missingLettersReplacedByNumbers [Fix #313]

exercises/pangram/src/test/java/PangramsTest.java

 
     @Ignore
     @Test
-    public void missingLettersReplacedByNumbersIsNotPangram() {
+    public void phraseWithMissingLettersReplacedByNumbersIsNotPangram() {
         assertFalse(Pangrams.isPangram("\"7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog\""));
     }