Merge "Cleanup some incorrect return annotations"

diff --cc includes/GlobalFunctions.php
Simple merge

diff --cc includes/OutputPage.php
Simple merge

diff --cc includes/Revision.php
Simple merge

diff --cc includes/WebRequest.php
Simple merge

diff --cc includes/api/ApiBase.php
Simple merge

diff --cc includes/diff/DifferenceEngine.php
Simple merge

diff --cc languages/Language.php
Simple merge