[selectors] Per WG resolution, specify that in level 4, CSS selectors (for style rules) *must* use the fast profile, not the complete profile.

Author: tabatkins

selectors/Overview.html

@@ -1232,6 +1232,10 @@ <h3 id=profiles><span class=secno>2.1. </span> <a
     profile. It includes all of the selectors defined in this document.
   </dl>
 
+  <p>CSS implementations conformant to Selectors Level 4 must use the ‘<a
+   href="#fast-profile"><code class=css>fast</code></a>’ profile for CSS
+   selection.
+
   <h2 id=syntax><span class=secno>3. </span> Selector Syntax and Structure</h2>
 
   <h3 id=structure><span class=secno>3.1. </span> Structure and Terminology</h3>

selectors/Overview.src.html

@@ -552,6 +552,8 @@ <h3 id="profiles">
       It includes all of the selectors defined in this document.
   </dl>
 
+  <p>CSS implementations conformant to Selectors Level 4 must use the ''fast'' profile for CSS selection.
+
 
 <h2 id="syntax">
 Selector Syntax and Structure</h2>