man: ip-rule.8: Review synopsis section

Clarify that 'ip rule' defaults to action 'list', that 'flush' and
'save' actions don't accept additional parameters, add missing 'not' and
'goto' keywords and finally fix fonts used in 'fwmark' and 'realms'
parameters.
Signed-off-by: Phil Sutter <phil@nwl.cc>

man/man8/ip-rule.8

@@ -9,20 +9,26 @@ ip-rule \- routing policy database management
 .B ip
 .RI "[ " OPTIONS " ]"
 .B rule
-.RI " { " COMMAND " | "
+.RI "{ " COMMAND " | "
 .BR help " }"
 .sp
 
 .ti -8
 .B  ip rule
-.RB " [ " list " | " add " | " del " | " flush " | " save " ]"
+.RB "[ " list " ]"
+
+.ti -8
+.B  ip rule
+.RB "{ " add " | " del " }"
 .I  SELECTOR ACTION
 
 .ti -8
-.B  ip rule  " restore "
+.B ip rule
+.RB "{ " flush " | " save " | " restore " }"
 
 .ti -8
 .IR SELECTOR " := [ "
+.BR not " ] ["
 .B  from
 .IR PREFIX " ] [ "
 .B  to
@@ -30,7 +36,7 @@ ip-rule \- routing policy database management
 .B  tos
 .IR TOS " ] [ "
 .B  fwmark
-.IR FWMARK[/MASK] " ] [ "
+.IR FWMARK\fR[\fB/\fIMASK "] ] [ "
 .B  iif
 .IR STRING " ] [ "
 .B  oif
@@ -45,8 +51,9 @@ ip-rule \- routing policy database management
 .B  nat
 .IR ADDRESS " ] [ "
 .B realms
-.RI "[" SRCREALM "/]" DSTREALM " ]"
-.I  SUPPRESSOR
+.RI "[" SRCREALM "\fB/\fR]" DSTREALM " ] ["
+.B goto
+.IR NUMBER " ] " SUPPRESSOR
 
 .ti -8
 .IR SUPPRESSOR " := [ "