Emoji selection looks bad

[zeozeozeo]

This was discovered in #3. It is caused by the new egui 0.29.1 selection rendering.

This code is the culprit:

egui-twemoji/src/lib.rs

Lines 315 to 319 in dc65224

	// for emoji selection and copying:
	resp |= ui.put(
	image_rect,
	egui::Label::new(RichText::new(emoji).color(egui::Color32::TRANSPARENT)),
	);

The library should somehow render the emojis over the selection.