Update README.md

Co-authored-by: Robert Adam <dev@robert-adam.de>

README.md

@@ -88,7 +88,7 @@ $ docker run -e "MUMBLE_CONFIG_SERVER_PASSWORD=123"
 
 Note: In the unlikely case where a `<configName>` setting is unknown to the container, startup will fail. The root cause of this error is the fact that
 this setting is incorrectly registered in the Mumble server code. You can workaround this error by setting the `MUMBLE_ACCEPT_UNKNOWN_SETTINGS` 
-environment variable to true and spelling `<configName>` exactly as written in [Murmur.ini](https://wiki.mumble.info/wiki/Murmur.ini) documentation.
+environment variable to `true` and spelling `<configName>` exactly as written in the [Murmur.ini](https://wiki.mumble.info/wiki/Murmur.ini) documentation.
 
 
 ### Additional variables