update enum converter

Author: h908714124

core/src/main/java/net/jbock/contrib/EnumConverter.java

@@ -47,7 +47,7 @@ protected E convert(String token) {
         } catch (IllegalArgumentException e) {
             String strings = values.get().stream()
                     .map(Objects::toString)
-                    .collect(joining("\n  ", "", ""));
+                    .collect(joining("\n  ", "", "\n"));
             String message = e.getMessage() + "\nPossible values:\n  " + strings;
             throw new IllegalArgumentException(message);
         }

examples/src/test/java/net/jbock/examples/CpArgumentsTest.java

@@ -27,7 +27,7 @@ void enumValuesInMessage() {
                         "  NONE\n" +
                         "  NUMBERED\n" +
                         "  EXISTING\n" +
-                        "  SIMPLE");
+                        "  SIMPLE\n");
     }
 
     @Test