Add support for Question-related message shortcodes

[joshfeck]

Reported here:

https://eventespresso.com/topic/recipient_question_list-not-functional-in-automatic-reminder/

We chatted about this in Slack and I wanted to make sure the idea didn't get lost. Tony came up with this:

    protected function _set_valid_shortcodes()
    {
        parent::_set_valid_shortcodes();
        foreach ($this->_valid_shortcodes as $context => $shortcodes) {
            $this->_valid_shortcodes[ $context ][] = 'question_list';
            $this->_valid_shortcodes[ $context ][] = 'question';
        }
    }

Which adds support for the QUESTION LIST & QUESTION shortcodes.

https://monosnap.com/file/eAEOb5Uzk9E2c4KRITYRhiQjdtx4zi

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.