doc: add doc.Example.Unordered to go1.7.txt

Change-Id: I142a9f97303e3bfbd9522fd061530c0a91305389
Reviewed-on: https://go-review.googlesource.com/20500Reviewed-by: Minux Ma <minux@golang.org>

doc/go1.7.txt

@@ -18,3 +18,4 @@ runtime: add CallerFrames and Frames (CL 19869)
 testing/quick: now generates nil values (CL 16470)
 net/url: support query string without values (CL 19931)
 net/textproto: permit all valid token chars in CanonicalMIMEHeaderKey input (CL 18725)
+go/doc: add Unordered boolean to Example struct (CL 19280)