Updated mediawiki/extensions
Project: mediawiki/extensions/TimedMediaHandler  6403e26d742e4761a94a20ea758bf792eba44a61

Consistency tweak: html5 -> HTML5

Spotted by Shirayuki
https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Mwe-embedplayer-for_best_experience/en

Change-Id: Ied4d30fbf067ff1a004c2ddd2906a3d4c6e4aa1a