Don't show the popup immediately on pressing hold keys

[birtles]

Currently, if you have "hold keys" configured (i.e. so you press Alt or Ctrl or both to make the popup show) then the moment you press those keys, if the cursor happens to be over Japanese text, the popup will show.

That might be a good idea sometimes but it trips me up all the time when using Gmail. If I'm composing a mail and press Ctrl + V very often the cursor is hovering over some other Japanese text in the same input box, and the Ctrl press triggers the popup, which triggers the text selection, and I end up clobbering some random text instead.

We should either not do the instantaneous popup when the focus is in a text box, or just not do it at all. The latter might even be as simple as dropping these lines:

10ten-ja-reader/src/content.ts

Lines 298 to 301 in de4dcf9

	if (this.currentPoint && this.currentTarget) {
	this.tryToUpdatePopup(this.currentPoint, this.currentTarget, 'default');
	ev.preventDefault();
	}

I'm a bit afraid this might break things for someone or make it harder to use, however.