IME preedit text field colors are currently hard coded (make them part of the color scheme)

[christianparpart]

they should be read from the color scheme, defaulting to the colors (and style state) that we're having right now.

Not sure it's a good thing, but whether or not to use bold text for rendering it, should probably be made configurable as well. But this is up for consideration only.

contour/src/vtbackend/RenderBufferBuilder.cpp

Lines 587 to 590 in c7ce541

	auto textAttributes = GraphicsAttributes {};
	textAttributes.foregroundColor = RGBColor(0xFF, 0xFF, 0xFF);
	textAttributes.backgroundColor = RGBColor(0xFF, 0x00, 0x00);
	textAttributes.flags |= CellFlags::Bold | CellFlags::Underline;