Update docs for DNS settings etc. (#3936)

* Update docs for DNS settings of the services which need its CNAME record by default

- Buscarron
- Go-NEB; fix a line on the instruction as well
- wsproxy
- Cinny
- Element Web
- Hydrogen
- SchildiChat Web
- Dimension
- Etherpad
- Jitsi
- ntfy
- Grafana
- rageshake
- Sygnal

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

* Update docs for DNS settings of the services which do not need its CNAME record by default

- matrix-alertmanager-receiver
- Honoroit
- maubot
- Heisenbridge
- Cactus Comments
- Matrix Authentication Service
- matrix-registration
- Sliding Sync proxy
- Synapse Admin
- synapse-usage-exporter

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

* Update docs for DNS settings: ma1sd

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

* Update docs for DNS settings: Email2Matrix

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

* Update docs for DNS settings: Postmoogle

Remove the table from configuring-dns.md altogether

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

* Update docs for Cinny and Dimension: adopt the common note

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

* Update docs/configuring-dns.md: add "Note" to the line on using Cloudflare DNS

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

---------

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

docs/configuring-playbook-alertmanager-receiver.md

@@ -36,6 +36,12 @@ For each new room you would like the bot to deliver alerts to, invite the bot to
 
 Then, log in as the bot using any Matrix client of your choosing, accept the room invitation from the bot's account, and log out.
 
+## Adjusting DNS records (optional)
+
+By default, this playbook installs matrix-alertmanager-receiver on the `matrix.` subdomain, at the `/matrix-alertmanager-receiver` path (https://matrix.example.com/matrix-alertmanager-receiver). This makes it easy to install it, because it **doesn't require additional DNS records to be set up**. If that's okay, you can skip this section.
+
+If you wish to adjust it, see the section [below](#adjusting-the-matrix-alertmanager-receiver-url-optional) for details about DNS configuration.
+
 ## Adjusting the playbook configuration
 
 Add the following configuration to your `inventory/host_vars/matrix.example.com/vars.yml` file. Make sure to replace `ACCESS_TOKEN_HERE` with the one created [above](#obtain-an-access-token).
@@ -61,9 +67,7 @@ matrix_alertmanager_receiver_config_matrix_room_mapping:
 
 See `roles/custom/matrix-alertmanager-receiver/defaults/main.yml` for additional configuration variables.
 
-### Adjusting the matrix-alertmanager-receiver URL
-
-By default, this playbook installs matrix-alertmanager-receiver on the `matrix.` subdomain, at the `/matrix-alertmanager-receiver` path (https://matrix.example.com/matrix-alertmanager-receiver). This makes it easy to install it, because it **doesn't require additional DNS records to be set up**. If that's okay, you can skip this section.
+### Adjusting the matrix-alertmanager-receiver URL (optional)
 
 By tweaking the `matrix_alertmanager_receiver_hostname` and `matrix_alertmanager_receiver_path_prefix` variables, you can easily make the service available at a **different hostname and/or path** than the default one.
 
@@ -75,13 +79,9 @@ matrix_alertmanager_receiver_hostname: alertmanager.example.com
 matrix_alertmanager_receiver_path_prefix: /
 ```
 
-## Adjusting DNS records
+If you've changed the default hostname, you may need to create a CNAME record for the matrix-alertmanager-receiver domain (`alertmanager.example.com`), which targets `matrix.example.com`.
 
-If you've changed the default hostname, **you may need to adjust your DNS** records to point the matrix-alertmanager-receiver domain to the Matrix server.
-
-See [Configuring DNS](configuring-dns.md) for details about DNS changes.
-
-If you've decided to use the default hostname, you won't need to do any extra DNS configuration.
+When setting, replace `example.com` with your own.
 
 ## Installing