docs(vs2015): remove duplicated word (#2441)

Author: trotyl

public/docs/ts/latest/cookbook/visual-studio-2015.jade

@@ -102,7 +102,7 @@ h2#restore Step 5: Restore the required packages
   * Ignore the warnings.
   * When the restore is finished, a message should say: `npm command completed with exit code 0`.
   * Click the `Refresh` icon in Solution Explorer.
-  * **Do not** include the `node_modules` folder in the project. Let it be a hidden project project folder.
+  * **Do not** include the `node_modules` folder in the project. Let it be a hidden project folder.
 .alert.is-important
   :marked
     An error such as "*@angular/compiler is not in the npm registry*" suggests that Visual Studio 2015