Xml:lang ref and rfc4646

Hi Richard, Felix, all,

One question. We have a new paragraph that mention xml:lang values:

<p>Applying the language information data category to <att>xml:lang</att> attributes using global
rules is not necessary, since <att>xml:lang</att> is already defined in terms of
<ptr target="#rfc4646" type="bibref"/>.</p>

Our current wording mentions RFC-4646, while (as far as know) the XML specification still refer to RFC-3066 (and do not say nything
about its successor). I assume we need to change our metion to RFC-3066, currently it's just incorrect.

Also I assume RFC-4646 is backward compatible with RFC-3066. Correct, otherwise we are in trouble for langRule.

So I would propose:

<p>Applying the language information data category to <att>xml:lang</att> attributes using global
rules is not necessary, since <att>xml:lang</att> is defined in terms of <ptr target="#rfc3066" type="bibref"/> (with which <ptr
target="#rfc3066" type="bibref"/> is compatible).</p>

Any thoughts?
-yves