Remove @author tags (#5601)

Our files are up to a decade old, and have churned so much, that the initial author of the file no longer has much meaning.

Furthermore, this will encourage developers to post to the developer group, rather than emailing Googlers (usually me) directly.

generators/dart.js

@@ -6,7 +6,6 @@
 
 /**
  * @fileoverview Helper functions for generating Dart for blocks.
- * @author fraser@google.com (Neil Fraser)
  */
 'use strict';