sorttable bug: data-attributes

summary: use data attributes or classes rather than custom sorttable attributes
class: wish · wish (a nice-to-have)
priority: medium · This should be fixed as soon as, but probably isn't important enough for the next release
fixed-in:
depends:

Currently we use sorttable_customkey as a custom attribute, which means that HTML
doesn’t validate. Validation would require one of the following: