Add note about git add for rsync tracking (#41605)

* Add note about git add for rsync tracking

tools/cli/README.md

@@ -1,6 +1,6 @@
 # jetpack CLI
 
-The `jetpack` CLI tool is used to help with development in [the Jetpack monorepo].
+The `jetpack` CLI tool is used to help with development in [the Jetpack monorepo](https://github.com/Automattic/jetpack).
 
 ## Installation
 
@@ -96,8 +96,7 @@ Watch a monorepo project, which will rebuild the project as changes are made so
 Maybe you'd prefer to develop against a live site instead of Docker. Or maybe you want to quickly push the plugin you're building to a live JN site without waiting for the builds. This rsync wrapper knows which files to send and not send. 
 
 - Rsync the Jetpack plugin to server destination: `jetpack rsync jetpack [email protected]:/home/path/to/wp-content/plugins`
-
-[the Jetpack monorepo]: https://github.com/Automattic/jetpack
+- Note: You need to git add new files so jetpack rsync will take them into account.
 
 **Draft**: Enable or disable "draft mode" for the repo.