Forward Slack messages, files, and Later items to channels and threads using an invisible link

This script enhances Slack's forwarding functionality and bypasses the built-in button's inability to forward to threads. It works for top-level and threaded messages, canvases, lists, files, and Later items which have no built-in way of copying links to them. Set which message or file to forward by clicking the fast forward icon beside it, then click the rewind button in an input area to insert an invisible link to that item. Right-click the rewind button to clear the set item.