docs: add link to jxa extension

Updated deprecation notice for JXA support to link to the separate extension.

Author: idleberg

README.md

@@ -6,7 +6,7 @@
 [![Build](https://img.shields.io/github/actions/workflow/status/idleberg/vscode-applescript/default.yml?style=for-the-badge)](https://github.com/idleberg/vscode-applescript/actions)
 
 > [!IMPORTANT]
-> JXA support is now deprecated and has been moved to a separate extension.
+> JXA support is now deprecated and has been moved to a [separate extension](https://github.com/idleberg/vscode-jxa).
 > Please refer to the
 > [deprecation notice](https://github.com/idleberg/vscode-jxa/discussions/2) for
 > details.