Add link to manuals chat channel
On https://gitlab.com/inkscape/inkscape-docs/manuals (really, https://gitlab.com/inkscape/inkscape-docs/manuals/-/blob/master/README.md ), the link about the chat section says:
Anyone who edits the book can exchange short messages, files and snippets via chat with other contributors on Inkscape's chat platform. We do not have a dedicated channel yet, so the #general channel is currently the best place. For important topics, please use one of the other two communication channels.
Since there is channel for that now, the text could be updated to:
Anyone who edits the book can exchange short messages, files and snippets via chat with other contributors on Inkscape's chat platform, in the documentation channel.