Add a changelog entry about GNATtest vscode integration improvement

Closes eng/ide/ada_language_server#1485

Author: eliericha

CHANGELOG.md

@@ -8,6 +8,7 @@ section below it for the last release. -->
 * Fix a bug that caused the ALS to hang when trying to complete partially qualified invisible symbols
 * Support loading a fresh checkout of an Alire crate by automatically performing the necessary Alire workspace initializations
 * VS Code status bar now displays an item showing the project-loading status and useful commands provided by the extension when hovering on it
+* Consider the `Gnattest.Harness_Dir` project attribute in the GNATtest integration in VS Code
 
 ## 26.0.202502240