[activitystreams] Issue: RFC 5646 listed as informative reference marked as i18n

r12a has just labeled an issue for 
https://github.com/w3c/activitystreams as "i18n":

== RFC 5646 listed as informative reference ==
Please Indicate One: 
 * [x] Editorial
 * [ ] Question
 * [ ] Feedback
 * [ ] Blocking Issue
 * [ ] Non-Blocking Issue

This issue has support from others in the i18n WG.

https://www.w3.org/TR/activitystreams-core/#normative-references

Leaving aside our recommendation that this should actually point to 
BCP47, this reference should be normative in order to ensure 
interoperability.  See for example, 
https://www.w3.org/TR/activitystreams-core/#naturalLanguageValues 
which says

> Every key in the object form MUST be a well-formed [RFC5646] 
Language-Tag.

(Note that this reference is a normative reference in 
https://www.w3.org/TR/activitystreams-vocabulary/#normative-references)


See https://github.com/w3c/activitystreams/issues/334