Description:
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The following pages properly document the return values of their respective functions but don't include the "Return Values" header line present on other function documentation pages. Adding this line to these pages would make their documentation easier to read:
http://www.php.net/manual/en/function.preg-grep.php
http://www.php.net/manual/en/function.preg-match-all.php
http://www.php.net/manual/en/function.preg-match.php
http://www.php.net/manual/en/function.preg-split.php

This page needs the "Return Values" line as well as clearer documentation on what values are returned:
http://www.php.net/manual/en/function.preg-quote.php

In addition to needing the "Return Values" line and clearer documentation on the returned values themselves, there is a typo in the existing documentation for this page. An apostrophe is needed in "functions":
http://www.php.net/manual/en/function.preg-replace-callback.php

Currently reads: "...do not clutter the function namespace with a callback functions name..."
Should read: "...do not clutter the function namespace with a callback function's name..."
                  ^^^