[html] Issue: Tighten up usages of "compatibilty caseless" comparisons used in the spec marked as i18n

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

== Tighten up usages of "compatibilty caseless" comparisons used in 
the spec ==
Cloned from bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=16970

Apparently compatibility caseless matching is used due to legacy IE 
behavior, though browsers are pretty inconsistent in to what extent 
this matching is implemented. The current spec leaves it relatively 
undefined to avoid the problem. There is general consensus that having
 compatibility caseless matching is a can of worms, and we would 
prefer to remove it from the spec. Can implementations align on 
something else? What is the impact to web content? These are some of 
the question that should be resolved.

Used in:

* `<map name="...">` - the name value of a map
* radio button name groups

See https://github.com/w3c/html/issues/216