[css-syntax] Specify that conformance checkers, if they do error recovery, have to work the same as user agents.

Author: tabatkins

css-syntax/Overview.html

@@ -562,7 +562,8 @@ <h2 id=tokenizing-and-parsing-css><span class=secno>3. </span> Tokenizing
    must not report parse error conditions if none exist in the document.
    Conformance checkers may report more than one parse error condition if
    more than one parse error condition exists in the document. Conformance
-   checkers are not required to recover from parse errors.
+   checkers are not required to recover from parse errors, but if they do,
+   they must recover in the same way as user agents.
 
   <h3 id=overview-of-the-parsing-model><span class=secno>3.1. </span>
    Overview of the Parsing Model</h3>

css-syntax/Overview.src.html

@@ -290,7 +290,9 @@ <h2>
 		and must not report parse error conditions
 		if none exist in the document.
 		Conformance checkers may report more than one parse error condition if more than one parse error condition exists in the document.
-		Conformance checkers are not required to recover from parse errors.
+		Conformance checkers are not required to recover from parse errors,
+		but if they do,
+		they must recover in the same way as user agents.
 
 <h3>
 Overview of the Parsing Model</h3>