Call for review: Add namespaced element references

Hey folks,

This pull request adds more uses of the new "namespaced element" definition
to our rules, making it more explicit what we mean when the rule says "HTML
element" or "SVG element": This review period lasts 1 week, ending on
October 14th. If you have any concerns with the change, please request
changes on the pull request before that date:
https://github.com/act-rules/act-rules.github.io/pull/1715/

-- 
*Wilco Fiers*
Axe-core product owner - Facilitator ACT Task Force - Co-chair ACT-Rules