doc: minor, styling
@@ -415,7 +415,7 @@ The system runlevel to go to after [bootstrap][] (S) has completed. `N`
is the runlevel number 0-9, where 6 is reserved for reboot and 0 for
halt.
-Default: 2
+*Default:* 2
> **Note:** only read and executed in runlevel S ([bootstrap][]).
