Readable debug output

Change-Id: I4110791832d2ab1d681b01c9e8a237567442c827
diff --git a/java/src/com/android/inputmethod/keyboard/KeyDetector.java b/java/src/com/android/inputmethod/keyboard/KeyDetector.java
index 0ce98d2..10cf1d1 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyDetector.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyDetector.java
@@ -267,7 +267,7 @@
                 addDelimiter = false;
             } else {
                 if (addDelimiter) sb.append(", ");
-                sb.append(code);
+                sb.append(Keyboard.printableCode(code));
                 addDelimiter = true;
             }
         }