[css-values] Define case-sensitivity of attr() to match attribute selectors.

Author: fantasai

css-values/Overview.bs

@@ -1898,6 +1898,8 @@ Ian's proposal:
 	(the qname production in [[!CSS3NAMESPACE]])
 	that represents an attribute name.
 	(In the absence of namespacing, this will just be a CSS identifier.)
+	As with <a href="https://www.w3.org/TR/selectors/#attribute-selectors">attribute selectors</a>,
+	the case-sensitivity of <<attr-name>> depends on the document language.
 
 	The optional <dfn>&lt;type-or-unit></dfn> argument is a keyword drawn from the list below that tells the UA how to interpret the attribute value,
 	and defines a type for the attr() expression.

css-values/issues-cr-2015.bsi

@@ -26,8 +26,7 @@ Comment:  https://lists.w3.org/Archives/Public/www-style/2015Jun/0271.html
 Response: ???
 Open:     Accepted
 Edits:    https://drafts.csswg.org/css-values-3/#calc-serialize
-Verified:
-Resolved: =WG= Discuss
+Resolved: https://lists.w3.org/Archives/Public/www-style/2016Apr/0093.html
 ----
 Issue 4.
 Summary:  Editorial nits
@@ -44,7 +43,7 @@ Comment:  https://lists.w3.org/Archives/Public/www-style/2015Dec/0150.html
 Response: https://lists.w3.org/Archives/Public/www-style/2015Dec/0258.html
 Open:     Accepted
 Verified: Reporter is editor
-Resolved: =WG= Discuss
+Resolved: ???
 ----
 Issue 6.
 Summary:  Percentages that are relative to other dimensions vs not.
@@ -143,8 +142,8 @@ From:     François Remy and David Baron
 Comment:  https://lists.w3.org/Archives/Public/www-style/2016Feb/0171.html
 Comment:  https://lists.w3.org/Archives/Public/www-style/2016Feb/0184.html
 Comment:  https://lists.w3.org/Archives/Public/www-style/2016Mar/0178.html
-Response:
-Open:
+Response: https://lists.w3.org/Archives/Public/www-style/2016Mar/0369.html
+Open:     Awaiting fixes to edits.
 ----
 Issue 18.
 Summary:  Implementations only drop calc() from "simple values" at computed-value time