Fix one typo
(it happened to be on the very method I was looking up to see what it was renamed to :)  )
@@ -133,7 +133,7 @@ Old name New name
``GitHub#iter_repo_issues`` ``GitHub#issues_on``
``GitHub#iter_keys`` ``GitHub#keys``
``GitHub#iter_orgs`` ``GitHub#{organizations,organizations_with}``
-``GitHub#iter_repos`` ``GitHub#reposistories``
+``GitHub#iter_repos`` ``GitHub#repositories``
``GitHub#iter_user_repos`` ``GitHub#repositories_by``
``GitHub#iter_user_teams`` ``GitHub#user_teams``
``Issue#iter_comments`` ``Issue#comments``
