fix(HTMLPurifier): typo FODLER => FOLDER
fix(HTMLPurifier): typo FODLER => FOLDER

cf. https://github.com/YesWiki/yeswiki/commit/64112be0bf5182ec4e01f8b74be50ea909798a33#commitcomment-85571790

YesWiki/yeswiki,YesWiki/yeswiki,YesWiki/yeswiki,YesWiki/yeswiki