Add two trivial PHPDocs lines to PhabricatorTypeaheadDatasource

Summary: Trivial but as I was looking into this code it cannot hurt I guess...

Test Plan: Manually check classes/types of parameters.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D26019

src/applications/typeahead/datasource/PhabricatorTypeaheadDatasource.php

@@ -135,6 +135,10 @@ abstract class PhabricatorTypeaheadDatasource extends Phobject {
   abstract public function getDatasourceApplicationClass();
   abstract public function loadResults();
 
+  /**
+   * @param $phase string
+   * @param $limit int
+   */
   protected function loadResultsForPhase($phase, $limit) {
     // By default, sources just load all of their results in every phase and
     // rely on filtering at a higher level to sequence phases correctly.