doc/go1.5.txt: mention sequential and RFC 6555-compliant TCP dialing

Change-Id: Ib0b0be901f2ed52e1b432ae62f0b1940eb27ecc3
Reviewed-on: https://go-review.googlesource.com/11137Reviewed-by: Ian Lance Taylor <iant@golang.org>

doc/go1.5.txt

@@ -58,6 +58,7 @@ math/big: add arbitrary precision Floats (many cl's)
 math/big: add Jacobi and Int.ModSqrt (https://golang.org/cl/1886)
 mime: add ExtensionByType (https://golang.org/cl/7444)
 mime/quotedprintable: new package (https://golang.org/cl/5940 + others)
+net: add sequential and RFC 6555-compliant TCP dialing (https://golang.org/cl/8768)
 net: add Source field to OpError (https://go-review.googlesource.com/9231)
 net: fix inconsistent errors (https://golang.org/cl/9236)
 net: add SocketConn, SocketPacketConn (https://golang.org/cl/9275)