Fix source error that was breaking the checklist dump.

(class="subtopic" incorrectly added to h4 heading)

index.html

@@ -2746,7 +2746,7 @@ <h3>Localization</h3>
 
 
 
-<section id="errors" class="subtopic">
+<section id="errors">
 <h4>Working with error and exception messages</h4>
 
 <p>Protocols, APIs, and document formats sometimes provide a field to pass a human-readable error or exception message from a service to the caller in the form of a string. In general, and as <a href="#l10n_api_message_metadata">indicated above</a>, any natural language text conveying human-readable messages or human-readable content needs to be associated with language and direction metadata. Where this metadata is missing, the processing or display of the text might be compromised.</p>