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-jitsi.md

@@ -281,7 +281,7 @@ You can use the self-hosted Jitsi server in multiple ways:
 
 - **by adding a widget to a room via Element** (the one configured by the playbook at `https://element.example.com`). Just start a voice or a video call in a room containing more than 2 members and that would create a Jitsi widget which utilizes your self-hosted Jitsi server.
 
-- **by adding a widget to a room via the Dimension Integration Manager**. You'll have to point the widget to your own Jitsi server manually. See our [Dimension](./configuring-playbook-dimension.md) documentation page for more details. Naturally, Dimension would need to be installed first (the playbook doesn't install it by default).
+- **by adding a widget to a room via the Dimension integration manager**. You'll have to point the widget to your own Jitsi server manually. See our [Dimension integration manager](./configuring-playbook-dimension.md) documentation page for more details. Naturally, Dimension would need to be installed first (the playbook doesn't install it by default).
 
 - **directly (without any Matrix integration)**. Just go to `https://jitsi.example.com`