Update readme

Author: kraigb

README.md

@@ -3,7 +3,7 @@
 * This sample contains the completed program from the tutorial, make sure to visit the link: [Using Flask in Visual Studio Code](https://code.visualstudio.com/docs/python/tutorial-flask). Intermediate steps are not included.
 * It also contains the Dockerfile and uwsgi.ini files necessary to build a container with a production server. The resulting image works both locally and when deployed to Azure App Service. See [Deploy Python using Docker containers](https://code.visualstudio.com/docs/python/tutorial-deploy-containers).
 * To run the app:
-  1. Run the command `cd hello_app`, which is the folder that contains the Flask app.
+  1. Run the command `cd hello_app`, to change into the folder that contains the Flask app.
   1. Run the command `set FLASK_APP=webapp` (Windows cmd) or `FLASK_APP=webapp` (macOS/Linux) to point to the app module.
   1. Start the Flask server with `flask run`.