Improve documentation.

includes/FeedsSource.inc

@@ -61,10 +61,10 @@ interface FeedsSourceInterface {
  * therefore a FeedsImporter never holds a pointer to a FeedsSource object, nor
  * does it hold any other information for a particular FeedsSource object.
  *
- * FeedsPlugins that implement FeedsSourceInterface and return TRUE on
- * hasSourceConfig() can define default values and forms that allow for
- * configuration of the FeedsSource. For an example, see FeedsFetcher and
- * FeedsHTTPFetcher.
+ * Classes extending FeedsPlugin can implement a sourceForm to expose
+ * configuration for a FeedsSource object. This is for instance how FeedsFetcher
+ * exposes a text field for a feed URL or how FeedsCSVParser exposes a select
+ * field for choosing between colon or semicolon delimiters.
  *
  * It is important that a FeedsPlugin does not directly hold information about
  * a source but leave all storage up to FeedsSource. An instance of a
@@ -72,9 +72,7 @@ interface FeedsSourceInterface {
  * instance of a FeedsSource class exists once per feed_nid to be imported.
  *
  * As with FeedsImporter, the idea with FeedsSource is that it can be used
- * without actually saving the object to the database (
- *
- * @todo Test whether FeedsSource can be used without saving it.
+ * without actually saving the object to the database.
  */
 class FeedsSource extends FeedsConfigurable {