Test Double subscripts
Test Double subscripts

* see https://phabricator.wikimedia.org/T78518
* seems to be fixed during regular MathJax (node) updates

Bug: T78518
Change-Id: Ia41509359db6aef29f8bfabd6b3114275daf822e

kwangkim/mathoid,kwangkim/mathoid,physikerwelt/mathoid-server,physikerwelt/mathoid-server,wikimedia/mathoid,kwangkim/mathoid,MonashAlexandria/mathoid,wikimedia/mathoid,wikimedia/mathoid,physikerwelt/mathoid-server,kwangkim/mathoid,wikimedia/mathoid,MonashAlexandria/mathoid