Improve phrasing.

wiki/src/contribute/design.mdwn

@@ -1391,7 +1391,7 @@ UDP and IPv6 are a problem. The Tor network does not support any of
 those yet. Outgoing UDP and IPv6 packets are dropped altogether by
 netfilter for this reason.
 
-Support of [[!tails_ticket 6070 desc="arbitrary DNS queries"]] is not
+Support for [[!tails_ticket 6070 desc="arbitrary DNS queries"]] is not
 provided anymore since we removed ttdnsd in Tails 3.0.
 
 Some tools currently available to command-line users lack the