ip-address.8.in: fix BNF syntax error

The previous man page fixup introduced a syntax error due to missing
opening bracket, which might crash some humanoid BNF parsers.

Fixes: 4e972d5e ("ip-address: fix and extend documentation")
Signed-off-by: Phil Sutter <phil@nwl.cc>

man/man8/ip-address.8.in

@@ -60,7 +60,7 @@ ip-address \- protocol address management
 .IR FLAG " := "
 .RB "[ " permanent " | " dynamic " | " secondary " | " primary " | \
 [ - ] " tentative " | [ - ] " deprecated " | [ - ] " dadfailed " | "\
-temporary " ] " CONFFLAG-LIST " ]"
+temporary " ] [ " CONFFLAG-LIST " ]"
 
 .ti -8
 .IR CONFFLAG-LIST " := [ "  CONFFLAG-LIST " ] " CONFFLAG