genericDisplay: Remove unused module

GenericDisplay used to provide a common base class for places and
recent items, none of which exists anymore. As of current mockups,
display items in "Finding and Reminding" should be based on
BaseIcon / IconGrid instead.

js/misc/docInfo.js

@@ -60,8 +60,7 @@ function getDocManager() {
 }
 
 /**
- * DocManager wraps the DocSystem, primarily to expose DocInfo objects
- * which conform to the GenericDisplay item API.
+ * DocManager wraps the DocSystem, primarily to expose DocInfo objects.
  */
 function DocManager() {
     this._init();