Fix capitalization: Dimension Integration Manager → Dimension integration manager

Based on https://github.com/turt2live/matrix-dimension
> An open source integration manager for matrix clients, like Element.

"Dimension" is one of the integration managers, and it is not something like Dimension Integration Manager, which could be abbreviated as DIM.

Also:
- Replace "integrations manager" with "integration manager"
- Fix typos
- Remove a line break

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

docs/configuring-playbook-etherpad.md

@@ -1,6 +1,6 @@
 # Setting up Etherpad (optional)
 
-[Etherpad](https://etherpad.org) is an open source collaborative text editor that can be embedded in a Matrix chat room using the [Dimension integrations manager](https://dimension.t2bot.io) or used as standalone web app.
+[Etherpad](https://etherpad.org) is an open source collaborative text editor that can be embedded in a Matrix chat room using the [Dimension integration manager](https://dimension.t2bot.io) or used as standalone web app.
 
 When enabled together with the Jitsi audio/video conferencing system (see [our docs on Jitsi](configuring-playbook-jitsi.md)), it will be made available as an option during the conferences.
 
@@ -60,7 +60,7 @@ 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)
+### How to use Etherpad widgets without an integration manager (like Dimension)
 
 This is how it works in Element, it might work quite similar with other clients: