modules/carrierroute Improved documentation of carrierroute reply_code field

The documentation didn't make it clear that regex are _not_ supported.
Thanks go to Iñaki Baz Castillo for reporting.

modules/carrierroute/README

@@ -976,12 +976,14 @@ domain register {
    for example that indicates that ringing has happened. If this flag is
    set, there will be no further forwarding, because next_domain is empty.
    In the second and third routes are certain gateway errors matched, if
-   this errors have occured, then the next domain will be choosen. The
-   last route does forwarding according some flags, e.g. the customer came
-   from a certain carrier, and has call-forwarding deactivated. In order
-   to use the routing that is specified above, a matching carrierroute
-   table must be provided, that holds domain entries for this routing
-   rules. Not all table colums are show here for brevity.
+   this errors have occured, then the next domain will be choosen. Note
+   that the reply_code must be 3 characters wide, and only the "."
+   character is accepted as wildcard.The last route does forwarding
+   according some flags, e.g. the customer came from a certain carrier,
+   and has call-forwarding deactivated. In order to use the routing that
+   is specified above, a matching carrierroute table must be provided,
+   that holds domain entries for this routing rules. Not all table colums
+   are show here for brevity.
 
    Example 1.23. Example database content - carrier_name table
 ...

modules/carrierroute/doc/carrierroute_admin.xml

@@ -1083,8 +1083,9 @@ domain register {
 			for example that indicates that ringing has happened. If this flag is set,
 			there will be no further forwarding, because next_domain is empty. In the
 			second and third routes are certain gateway errors matched, if this errors
-			have occured, then the next domain will be choosen. The last route does
-			forwarding according some flags, e.g. the customer came from a certain carrier,
+			have occured, then the next domain will be choosen. Note that the reply_code must be
+			3 characters wide, and only the "." character is accepted as wildcard.The last route
+			does forwarding according some flags, e.g. the customer came from a certain carrier,
 			and has call-forwarding deactivated. In order to use the routing that is
 			specified above, a matching carrierroute table must be provided, that holds
 			domain entries for this routing rules. Not all table colums are show here for