Fixed broken link in playground examples : this.ts (#3174)

Author: Ptitet

packages/playground-examples/copy/en/JavaScript/Working With Classes/This.ts

@@ -88,4 +88,4 @@ customObjectTryingToChangeThis.print();
 
 // You can learn more about that in the handbook:
 //
-// https://www.typescriptlang.org/docs/handbook/utility-types.html#thistypet
+// https://www.typescriptlang.org/docs/handbook/utility-types.html#thistypetype