net: fix consecutive dialing docs

Update #17617.

Change-Id: Ia0bc9954bb914b650b7c7af35ef714ca6b0740b4
Reviewed-on: https://go-review.googlesource.com/34376Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/dial.go

@@ -265,7 +265,7 @@ func (r *Resolver) resolveAddrList(ctx context.Context, op, network, addr string
 //	Dial("ip6:ipv6-icmp", "2001:db8::1")
 //
 // For Unix networks, the address must be a file system path.
-
+//
 // If the host is resolved to multiple addresses,
 // Dial will try each address in order until one succeeds.
 func Dial(network, address string) (Conn, error) {
@@ -302,11 +302,13 @@ func (d *Dialer) Dial(network, address string) (Conn, error) {
 // connected, any expiration of the context will not affect the
 // connection.
 //
-// If the host in the address parameter resolves to multiple network addresses,
-// and if a timeout is given, the connection to each address is given an
-// appropriate fraction of the time to connect. For example, if a host has
-// 4 IP addresses and the timeout is 1 minute, the connect to each single
-// address will be given 15 seconds to complete before trying the next one.
+// When using TCP, and the host in the address parameter resolves to multiple
+// network addresses, any dial timeout (from d.Timeout or ctx) is spread
+// over each consecutive dial, such that each is given an appropriate
+// faction of the time to connect.
+// For example, if a host has 4 IP addresses and the timeout is 1 minute,
+// the connect to each single address will be given 15 seconds to complete
+// before trying the next one.
 //
 // See func Dial for a description of the network and address
 // parameters.