copy tweak for installing vsce

Author: jeff-allen-mongo

source/includes/steps-install-vsce.yaml

@@ -20,4 +20,8 @@ ref: search-mongodb-for-vscode
 title: Click :guilabel:`Install` on the "MongoDB for VS Code" extension.
 level: 4
 ref: click-install
+content: |
+   Once the installation is complete, the :guilabel:`Install` button
+   changes to the :guilabel:`Manage` gear button.
+
 ...