Update script execution documentation (#17147)

Removed reference to **Scripts** tab and added instructions for
accessing the **Run Script** modal from the host detail page.

# Checklist for submitter

Docs-only change

---------

Co-authored-by: Brock Walters <[email protected]>
Co-authored-by: Rachael Shaw <[email protected]>

Author: 3 people

docs/Using Fleet/Scripts.md

@@ -30,7 +30,11 @@ Fleet UI:
 
 2. Head to the **Hosts** page and select the host you want to run the script on.
 
-3. On your target host's host details page, select the **Scripts** tab and select **Actions** to run the script.
+3. On your target host's host details page, select the **Actions** dropdown and select **Run Script** to view the **Run Script** menu.
+   
+4. In the **Run Script** menu, select the **Actions** dropdown for the script you'd like to execute and choose the **Run** option.
+
+Scripts run from the Fleet UI will run the next time your host checks in with Fleet. You can view the status of the script execution as well as the output in the target host's activity feed.
 
 Fleet API: API documentation is [here](https://fleetdm.com/docs/rest-api/rest-api#run-script)