append es2017.string into Jakefile

Author: imcotton

Jakefile.js

@@ -303,7 +303,8 @@ var es2016LibrarySourceMap = es2016LibrarySource.map(function (source) {
 
 var es2017LibrarySource = [
     "es2017.object.d.ts",
-    "es2017.sharedmemory.d.ts"
+    "es2017.sharedmemory.d.ts",
+    "es2017.string.d.ts",
 ];
 
 var es2017LibrarySourceMap = es2017LibrarySource.map(function (source) {