Default drag.touchable should use navigator.maxTouchPoints, if supported?

[Herst]

See https://crbug.com/392584

No idea what d3.js could or should do about it, probably do nothing and just add a note to the documentation of drag.touchable?

(Or use navigator.maxTouchPoints/window.matchMedia("(any-pointer)")?)

[altocumulus]

With the release of Chrome v70 this seems to have become an issue: "Touch handling completely broken on Chrome version 70".

[mbostock]

You can use drag.touchable(navigator.maxTouchPoints) or similar if you want to change how d3-drag detects support for touch.

[Herst]

Firefox followed suit: https://bugzil.la/1412485 (see also https://www.fxsitecompat.com/en-CA/docs/2019/legacy-touch-events-api-is-now-disabled-on-desktop/)