[url] be explicit about change control issue (#37)

the issue of change control, stability, normative references should be explicit.

It is unlikely to get IETF to replace a Proposed Standard much less a Standard with a normative reference to a Living Standard given IETF policy on normative references (which should be linked).



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Reply to this email directly or view it on GitHub:
https://github.com/webspecs/url/issues/37