[selectors-4] Clarify that selectors not in the dynamic profile must be treated as invalid for dynamic usages. Tweak some linking text.

Author: tabatkins

selectors/Overview.bs

@@ -465,7 +465,7 @@ Selectors Overview</h2>
 	To accommodate this, two profiles of the Selectors spec are defined:
 
 	<dl>
-		<dt><dfn id='dynamic-profile'>dynamic</dfn>
+		<dt><dfn local-lt="dynamic">dynamic profile</dfn>
 		<dd>
 			The <a>dynamic</a> profile is appropriate for use in any context,
 			including dynamic browser CSS selector matching.
@@ -476,7 +476,7 @@ Selectors Overview</h2>
 				<li>The '':has()'' pseudo-class
 			</ul>
 
-		<dt><dfn id='static-profile'>static</dfn>
+		<dt><dfn local-lt="static">static profile</dfn>
 		<dd>
 			The <a>static</a> profile is appropriate for contexts which aren't extremely performance sensitive;
 			in particular, it's appropriate for contexts which evaluate selectors against a static DOM.
@@ -485,6 +485,8 @@ Selectors Overview</h2>
 	</dl>
 
 	CSS implementations conformant to Selectors Level 4 must use the <a>dynamic</a> profile for CSS selection.
+	Implementations using the <a>dynamic</a> profile must treat selectors that are not included in the profile
+	as unknown and invalid.
 
 	<p class='issue'>
 		The categorization of things into the "dynamic" or "static" profiles needs implementor review.