Add Firefox versions for ProcessingInstruction API (#12121)
Add Firefox versions for ProcessingInstruction API (#12121)

This PR adds real values for Firefox and Firefox Android for the `ProcessingInstruction` API, based upon results from the [mdn-bcd-collector](https://mdn-bcd-collector.appspot.com) project (v3.2.9).

Tests Used: https://mdn-bcd-collector.appspot.com/tests/api/ProcessingInstruction
mdn/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data