net/http: export the "new" error codes from RFC 6585
These were proposed in the RFC over three years ago, then proposed to
be added to Go in https://codereview.appspot.com/
7678043/ 2 years and
7 months ago, and the spec hasn't been updated or retracted the whole
time.
Time to export them.
Of note, HTTP/2 uses code 431 (Request Header Fields Too Large).
Updates #12843
Change-Id: I78c2fed5fab9540a98e845ace73f21c430a48809
Reviewed-on: https://go-review.googlesource.com/15732
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>