Mention 203 Non-Authoritative Information in p1

[mnot@…]

We define 203 in p2 as being applicable when the content has been modified by an intermediary;

The 203 (Non-Authoritative Information) status code indicates that the request was successful but the enclosed payload has been modified from that of the origin server's 200 (OK) response by a transforming proxy (Section 5.7.2 of [Part1]). This status code allows the proxy to notify recipients when a transformation has been applied, since that knowledge might impact later decisions regarding the content. For example, future cache validation requests for the content might only be applicable along the same request path (through the same proxies).

However, 203 isn't mentioned anywhere in <​https://svn.tools.ietf.org/svn/wg/httpbis/draft-ietf-httpbis/latest/p1-messaging.html#message.transformations>. It seems like it should either be mentioned as an appropriate thing to use there, or deprecated.

[fielding@…]

From [2287]:

Mention 203 (Non-Authoritative Information) in description of payload transformations; addresses #465