ve.ui.Trigger: Clean up indentation and documentation

* One value per line, not arbitrarily adjacent values based on
  virtual groups or inline comments. In object literals I found
  especially confusing the the colons sprinkled throughout a line
  (like in .keyAliases and .primaryKeyMap)

* Add missing @inheritable.
* Remove redundant @method.
* Phrase the method summary in the imperative mood.

Change-Id: I283309df7afb719a09a084aa5b52b386f54d1036