Disable spellchecker popup on Android

On Android, there's a spellchecker popup that occasionally appears over the keyboard, getting very annoyingly in the way. See for example this unanswered question with screenshots . It looks like a feature of the keyboard, but it's not, and so I looked and I looked and I could not find how to turn it off. The answer is to look for how to disable the spellchecker in the keyboard section of the…