source-only change charter-template.html (#667)

fix HTML comment to be more accurate for its section

Author: tantek

charter-template.html

@@ -288,7 +288,7 @@ <h2>Success Criteria</h2>
 		Each specification should contain a section on accessibility that describes the benefits and impacts, including ways specification features can be used to address them, and
 		recommendations for maximising accessibility in implementations.</p>
 
-    <!-- W3C statements -->
+    <!-- W3C Statements and Web Platform Design Principles -->
     <p>This group is expected to be guided by the following documents:</p>
     <ul>
       <li><a href="https://www.w3.org/TR/ethical-web-principles/">Ethical Web Principles</a>,</li>