consistent error message for bad yaml element types

src/main/java/me/fallenbreath/yamlang/Yamlang2JsonlangMapper.java

@@ -53,7 +53,7 @@ else if (value instanceof Map)
 			}
 			else
 			{
-				throw new IllegalArgumentException(String.format("Unknown type %s in with key %s", value.getClass(), fullKey));
+				throw new IllegalArgumentException(String.format("Bad type %s for value %s on key %s", value.getClass(), value, fullKey));
 			}
 		});
 	}