[document_repository] Update help content (#8761)

Added reference to new feature to support uploading multiple files at once.

Author: jeffersoncasimir

modules/document_repository/help/document_repository.md

@@ -5,6 +5,6 @@ This module provides studies with a centralized location for important documents
 In the **Browse** tab, you can search for specific files using the **Selection Filter** section. Click on any file name in the data table to download. Click on any of the folders to reveal subfolders and files organized within. You can click on **Edit** or **Delete** in any cell, in those respective columns, to modify a file. Click on certain column headers to sort the list of documents.
 The **Filter globally** only works in the current directory (root folder only contains directories).
 The **Filter globally** will filter the file across the directories.
-Navigate to the **Upload** tab to upload a file. Populate the fields and upload your file. Your newly uploaded file should now appear in the list within the Browse tab.
+Navigate to the **Upload** tab to upload one or more files. Populate the fields and upload your files. Your newly uploaded files should now appear in the list within the Browse tab.
 
 If you need to add a new category or subcategory, you can do so in the **Category** tab. Populate the fields and click **Add Category**.