During the upgrade to 5.x, question categories are moved to new
mod_qbank module contexts, and any set references using those categories
are updated using `move_question_set_references()`. However, this
function wasn't updating the `cat` arribute of the set reference's
filter condition, leaving it pointing at the original context ID.
This change update `move_question_set_references()` so that when a set
reference is moved (during the 5.x upgrade, or otherwise) the `cat`
parameter will be updated correctly.
For sites that have already gone through the 5.x upgrade, this fix also
adds a CLI script to find and fix incorrect question_set_reference
records. I considered adding this as an upgrade step, but it potentially
has a lot of records to check, and it's redundant if the site is being
upgraded to 5.x with this fix already in place.
While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.
All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.
Mark Johnson