A small but important point to contend is not possible nor highly likely.
"We use telemetry data, including information about which suggestions users accept or reject, to improve the model," the Microsoft-owned biz said. "We do not reference your private code when generating code for other users."
Should that be written in the interest of greater accuracy for clearer transparency .... We do not reference Microsoft-owned biz use of your private code when generating code for other users ‽ .
It is Microsoft after all, which be infamous for its supposed Base DNA Proclivity of Embrace, Extend and Extinguish.
And if that blanket assumption be totally wrong, I apologise for the popular presumption of their unproven guilt in such matters as matter greatly.