Update README

Author: davidanthoff

README.md

@@ -6,4 +6,5 @@
 
 ## Overview
 
-This package provides the `@testitem` macro for the test runner feature in VS Code. You can learn more over at the [documentation](https://www.julia-vscode.org/docs/stable/userguide/testitems/) for the entire test item ecosystem.
+This package provides the `@testitem` macro for the test runner feature in VS Code. You can learn more over at the [documentation](https://www.julia-vscode.org/docs/stable/userguide/testitems/) for the entire test item ecosystem. Note that while the documentation is hosted as part of the Julia VS Code extension, the test item framework is not a VS Code extension specific technology and can be used entirely without VS Code.
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