It doesn’t appear that it is possible to turn off the stop/start feature in my 2018 Cruze. I even consulted the manual:
Makes no reference to turning off the stop/start, unlike some other manuals.
This button is absent in my 2019.
Thanks to ttyymmnn, looks like the ability to disable the stop/start was added for the 2019 model year:
Car in question is my rental Cruze.