When several library colors share the same RGB value but differ only
in opacity, append the alpha percentage (e.g. "#ff0000 50%") next to
the displayed default name and in the color bullet tooltip so users
can tell them apart at a glance.
Closes#6328
Signed-off-by: rockchris99 <chrisleo0721@gmail.com>
Co-authored-by: Andrey Antukh <niwi@niwi.nz>
8cc05d9579