Editorial changes from PR suggestions

Author: rbuckton

tslib.es6.js

@@ -116,7 +116,7 @@ export function __values(o) {
             return { value: o && o[i++], done: !o };
         }
     };
-    throw new TypeError(s ? "Object not iterable." : "Symbol.iterator is not defined.");
+    throw new TypeError(s ? "Object is not iterable." : "Symbol.iterator is not defined.");
 }
 
 export function __read(o, n) {

tslib.js

@@ -153,7 +153,7 @@ var __importDefault;
                 return { value: o && o[i++], done: !o };
             }
         };
-        throw new TypeError(s ? "Object not iterable." : "Symbol.iterator is not defined.");
+        throw new TypeError(s ? "Object is not iterable." : "Symbol.iterator is not defined.");
     };
 
     __read = function (o, n) {