Update docs/configuring-playbook-etherpad.md: remove the detail about setting the unmaintained Dimension default to the Etherpad instance

We have recommended users to avoid installing Dimension since it was deprecated, so it is no longer sensible to discuss how it could be integrated with Etherpad.

This commit also removes the known issue section as it describes the issue which can be experienced on Dimension only.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-etherpad.md

@@ -98,26 +98,8 @@ If you want to manage and remove old unused pads from Etherpad, you will first n
 
 Then from the plugin manager page (`https://etherpad.example.com/admin/plugins`, install the `adminpads2` plugin. Once installed, you should have a "Manage pads" section in the Admin web-UI.
 
-### How to use Etherpad widgets without an integration manager (like Dimension)
+### Integrating a Etherpad widget in a room
 
 This is how it works in Element Web, it might work quite similar with other clients:
 
 To integrate a standalone Etherpad in a room, create your pad by visiting `https://etherpad.example.com`. When the pad opens, copy the URL and send a command like this to the room: `/addwidget URL`. You will then find your integrated Etherpad within the right sidebar in the `Widgets` section.
-
-### Set Dimension default to the self-hosted Etherpad (optional)
-
-If you decided to install [Dimension integration manager](configuring-playbook-dimension.md) alongside Etherpad, the Dimension administrator users can configure the default URL template.
-
-The Dimension configuration menu can be accessed with the sprocket icon as you begin to add a widget to a room in Element Web. There you will find the Etherpad Widget Configuration action beneath the _Widgets_ tab.
-
-#### Removing the integrated Etherpad chat
-
-If you wish to disable the Etherpad chat button, you can do it by appending `?showChat=false` to the end of the pad URL, or the template.
-
-Example: `https://etherpad.example.com/p/$roomId_$padName?showChat=false`
-
-## Known issues
-
-If your Etherpad widget fails to load, this might be due to Dimension generating a Pad name so long, the Etherpad app rejects it.
-
-`$roomId_$padName` can end up being longer than 50 characters. You can avoid having this problem by altering the template so it only contains the three word random identifier `$padName`.