[css-syntax] Add a note about the handling of escapes in bad-url.

Author: tabatkins

css-syntax/Overview.html

@@ -2330,7 +2330,10 @@ <h4 id=consume-the-remnants-of-a-bad-url><span class=secno>4.3.14.
         valid escape</i></a>
 
        <dd> <a href="#consume-an-escaped-character0"><i>Consume an escaped
-        character</i></a>.
+        character</i></a>. <span class=note>This allows an escaped right
+        parenthesis ("\)") to be encountered without ending the
+        〈bad-url〉. This is otherwise identical to the "anything else"
+        clause.</span>
 
        <dt>anything else
 

css-syntax/Overview.src.html

@@ -1624,6 +1624,8 @@ <h4>
 		<dt>the input stream <i>starts with a valid escape</i>
 		<dd>
 			<i>Consume an escaped character</i>.
+			<span class='note'>This allows an escaped right parenthesis ("\)") to be encountered without ending the 〈bad-url〉.
+				This is otherwise identical to the "anything else" clause.</span>
 
 		<dt>anything else
 		<dd>