Update mobile-demo.md

Author: brucejlin1

_resources/mobile-demo.md

@@ -1,7 +1,7 @@
 ---
 title: Mobile Demo
 summary-home: Check out the PyTorch Mobile demo app for iOS and Android.
-summary: heck out the PyTorch Mobile demo app for iOS and Android.
+summary: Check out the PyTorch Mobile demo app for iOS and Android.
 class: pytorch-resource
 link: https://github.com/pytorch/android-demo-app
 order: 9