net/url: remove RFC 3986 mention in package comment

Change-Id: Ifd707a4bbfcb1721655b4fce2045f3b043e66818
Reviewed-on: https://go-review.googlesource.com/22859
Reviewed-by: Russ Cox <[email protected]>

Author: bradfitz

src/net/url/url.go

@@ -3,9 +3,13 @@
 // license that can be found in the LICENSE file.
 
 // Package url parses URLs and implements query escaping.
-// See RFC 3986.
 package url
 
+// See RFC 3986. This package generally follows RFC 3986, except where
+// it deviates for compatibility reasons. When sending changes, first
+// search old issues for history on decisions. Unit tests should also
+// contain references to issue numbers with details.
+
 import (
 	"bytes"
 	"errors"