PHP Manual user note integration in AGPLv3 project

Hi there, I've hit a compatibility issue in a PHP project under AGPLv3 that I've managed to fix using a few lines of code suggested by a user note <http://php.net/manual/en/function.hex2bin.php#113472> from PHP Manual. Now I'm submitting a pull request upstream, mainly to avoid me maintaining a patched version, and I wonder how to make this right. I've already credited the user note, but I guess that's not enough since it's covered by CC BY 3.0 like the whole PHP Manual. And I'm not sure upstream will handle the introduction of a another license if it has to come to that. I expect this to be a common issue you hopefully can help me to clarify soon: so what's your opinion on this? Is there a chance PHP Documentation Group would allow me/my employer to adapt a portion that code as a contribution to AGPLv3 project? Thanks for your help, bEn