In settings.json (under File, Preferences, Settings), I found that setting the more general option:
"editor.inlineSuggest.enabled": false,
Seems to work as I’d hoped. Copilot suggestions are now only provided on-demand, when I press Alt\, and accepted when I press Tab
I worry that this might disable other types of suggestions I rely on… but language auto-completion still seems to work. I’ll update this answer if I find anything I miss.
BTW, changing the keyboard shortcuts:
Under File, Preferences, Keyboard Shortcuts, if you search for inlinesuggest, you see the keystrokes for both triggering inline suggestion and for committing (aka, accepting) inline suggestions. Double-click the row to change the key (but watch out for conflicts.)
