Update docs/configuring-playbook-jitsi.md: remove a duplicated comment inside jitsi_web_custom_config_extension

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

docs/configuring-playbook-jitsi.md

@@ -159,7 +159,6 @@ jitsi_web_custom_config_extension: |
 
   config.disableAudioLevels = true;
 
-  // Limit the number of video feeds forwarded to each client
   config.channelLastN = 4;
 ```