Add section number to .Xr. Put arguments under .Ar.

usr.bin/rusers/rusers.1

@@ -46,10 +46,14 @@
 The
 .Nm
 command produces output similar to
-.Xr who ,
-but for the list of hosts or all machines on the local
+.Xr who 1 ,
+but for the list of
+.Ar host Ns s
+or all machines on the local
 network.
-For each host responding to the rusers query,
+For each
+.Ar host
+responding to the rusers query,
 the hostname with the names of the users currently logged
 on is printed on each line.
 The rusers command will wait for