Intent to ship: beforeinput event and InputEvent.getTargetRanges()

Since Nov. 2020, we enabled them by default in Nightly channel and early beta channel [1]. According to the telemetry [2], `beforeinput` events have not been used by most web apps which uses `designMode` or `contenteditable` (only 1.53%, 3k instances of `HTMLEditor`), but we know that this

Intent to Ship: Block HTTP ports 69, 137, 161, 1719, 1720, 1723, 6566, 10080

Hi, A couple of weeks ago, I have added the ports mentioned above to the existing list of blocked ports. The additional port blocking is in response to an improvement of last year's "NAT slipstreaming" attack, see footnote [1] for more. Again, we acknowledge that this stops an instance of the atta