Adjust blank lines: remove duplicated ones

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

docs/configuring-playbook-riot-web.md

@@ -7,7 +7,6 @@ Riot has since been [renamed to Element](https://element.io/blog/welcome-to-elem
 - to learn more about Element Web and its configuration, see our dedicated [Configuring Element Web](configuring-playbook-client-element-web.md) documentation page
 - to learn how to migrate from Riot to Element Web, see [Migrating to Element Web](#migrating-to-element-web) below
 
-
 ## Migrating to Element Web
 
 ### Migrating your custom settings
@@ -16,7 +15,6 @@ If you have custom `matrix_riot_web_` variables in your `inventory/host_vars/mat
 
 Some other playbook variables (but not all) with `riot` in their name are also renamed. The playbook checks and warns if you are using the old name for some commonly used ones.
 
-
 ### Domain migration
 
 We used to set up Riot at the `riot.example.com` domain. The playbook now sets up Element Web at `element.example.com` by default.
@@ -27,7 +25,6 @@ There are a few options for handling this:
 
 - (**embracing changes** - using only `element.example.com`) - set up the `element.example.com` DNS record (see [Configuring DNS](configuring-dns.md)). You can drop the `riot.example.com` in this case.
 
-
 ### Re-running the playbook
 
 After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below: