chore: update functionality.md

functionality.md

@@ -21,12 +21,22 @@ wowtools allows you to specify specific flags when calling the app from the CLI
   - Remove the WTF and Interface folder from your PTR install folder
   - Use Windows Robocopy to copy the WTF and Interface folder from your retail folder to the PTR folder.
 
+`addoncopy`
+
+- This flag will copy all or a specific addon from the retail folder to the folder of your choice
+  - If no `addonname` parameter is passed, it will copy all addons, first removing the destination folder
+  - If the parameter is passed, it will copy that specific addon, first deleting that folder in the destination
+
 `update`
 
 - This flag will run wowtools and _only_ do the following
   - Check the version of the application against the latest release on github
   - If the version is different, it will download the latest release to your downloads folder so you can replace the current executable
 
+`completion`
+
+- This flag will generate a completion script for the application based on the shell you select
+
 `help`
 
 - Shows help text for the application