Fixed formatting in PHPDoc

Author: sgrodzicki

lib/Github/Api/Repo.php

@@ -336,11 +336,11 @@ public function watchers($username, $repository, $page = 1)
      * Perform a merge
      * @link http://developer.github.com/v3/repos/merging/
      *
-     * @param string $username
-     * @param string $repository
-     * @param string $base The name of the base branch that the head will be merged into.
-     * @param string $head The head to merge. This can be a branch name or a commit SHA1.
-     * @param string $message Commit message to use for the merge commit. If omitted, a default message will be used.
+     * @param  string      $username
+     * @param  string      $repository
+     * @param  string      $base        The name of the base branch that the head will be merged into.
+     * @param  string      $head        The head to merge. This can be a branch name or a commit SHA1.
+     * @param  string      $message     Commit message to use for the merge commit. If omitted, a default message will be used.
      *
      * @return array|null
      */