doc: go1.6.txt: *url.Error implements net.Error

Change-Id: I34c8ada1f3c5d401944483df424011fa2ae9fc3d
Reviewed-on: https://go-review.googlesource.com/15673Reviewed-by: Dave Cheney <dave@cheney.net>

doc/go1.6.txt

@@ -13,6 +13,7 @@ bufio: add Scanner.Buffer (https://golang.org/cl/14599/)
 bufio: add ErrFinalToken as a sentinel value for Scan's split functions (https://golang.org/cl/14924)
 fmt: allow any integer type as an argument to the * operator (https://golang.org/cl/14491/)
 math/rand: add Read (https://golang.org/cl/14522)
+net/url: make *url.Error implement net.Error (https://golang.org/cl/15672)
 strconv: QuoteToGraphic (https://golang.org/cl/14184/)
 text/template: ExecError (https://golang.org/cl/13957/)
 text/template: trimming spaces (https://golang.org/cl/14391/)