net: fix Dial comment about IPv6 addresses

LGTM=r
R=golang-codereviews, r
CC=adg, golang-codereviews
https://golang.org/cl/118550043

src/pkg/net/dial.go

@@ -118,9 +118,8 @@ func resolveAddr(op, net, addr string, deadline time.Time) (netaddr, error) {
 // "unixpacket".
 //
 // For TCP and UDP networks, addresses have the form host:port.
-// If host is a literal IPv6 address or host name, it must be enclosed
-// in square brackets as in "[::1]:80", "[ipv6-host]:http" or
-// "[ipv6-host%zone]:80".
+// If host is a literal IPv6 address it must be enclosed
+// in square brackets as in "[::1]:80" or "[ipv6-host%zone]:80".
 // The functions JoinHostPort and SplitHostPort manipulate addresses
 // in this form.
 //