Add note about adb on PATH to nimbus-cli install guide (#708)

Author: freshstrangemusic

docs/deep-dives/mobile/nimbus-cli/10-install.mdx

@@ -14,6 +14,8 @@ It runs on macOS, Linux and Windows. It works with [`adb`](https://developer.and
 
 - Install [`adb`](https://developer.android.com/tools/adb), with Android Studio, or via [Platform Tools](https://developer.android.com/tools/releases/platform-tools).
 
+Ensure that `adb` is on your PATH. You may have to restart your shell.
+
 ### For working with iOS:
 
 - Install Xcode.