Update READMEs

Change-Id: Icc80888271feaa813c26d647ff4398f4a90a6e4d

Author: bsagmoe

README.md

@@ -4,6 +4,9 @@ This repository contains Android sample apps that are used in
 [Android XR](https://developer.android.com/xr) codelabs. The codelabs guide
 you through best practices of building apps for XR devices.
 
+- [Learn Android XR Fundamentals](/xr-fundamentals/)
+  - [Part 1 - Modes and Spatial Panels](https://developer.android.com/codelabs/xr-fundamentals-part-1)
+
 Clone the repo or download and unarchive the ZIP file. The folders in the repo
 contain Android Studio projects that enable you to modify and build the sample
 apps. The codelabs provide instructions on how to work with the apps.

xr-fundamentals/README.md

@@ -1,6 +1,6 @@
 # Learn Android XR Fundamentals
 
-This directory contains the code for the "Learn Android XR fundamentals" series
+This directory contains the code for the "Learn Android XR Fundamentals" series
 of codelabs:
 
-- [Learn Android XR Fundamentals: Part 1 - Modes and Panels](developer.android.com/codelabs/xr-fundamentals-part-1)
+- [Learn Android XR Fundamentals: Part 1 - Modes and Spatial Panels](https://developer.android.com/codelabs/xr-fundamentals-part-1)