[selectors] Update changes list (part I, rough draft)

Author: fantasai

selectors/Overview.bs

@@ -3451,6 +3451,23 @@ Changes</h2>
 	<ul>
 		<li>Split out <a>relative selectors</a> from <a>scoped selectors</a>,
 			as these are different concepts that can be independently invoked.
+		<li>Changed rules for absolutizing a relative selector.
+		Issue: List changes + rationale?
+		<li>Replaced subject indicator feature with '':has()''.
+		<li>Changed the <css>:active-drop-target</css>, <css>:valid-drop-target</css>, <css>:invalid-drop-target</css> with '':drop()''.
+		<li>Moved definition of <<An+B>> microsyntax to CSS Syntax.
+		Issue: Semantic definition should probably move back here.
+		<li>Added new sections:
+			<ul>
+				<li>Evaluating a Selector
+				Issue: https://lists.w3.org/Archives/Public/www-style/2015Mar/0432.html
+				<li>Data Model
+				Issue: Need to define tree for XML.
+				<li>API Hooks
+			</ul>
+		<li>Removed restriction on combinators within '':matches()'', '':not()'', '':nth-match()'', and '':nth-last-match()''. (????)
+		<li>Defined <a>specificity</a> of a <a>selector list</a>. (Why?)
+		<li>Removed the <css>:local-link</css> and reference combinator for lack of interest.
 	</ul>