Furnace progress textures duplicate the background color

The bug

The textures gui/sprites/container/furnace/burn_progress.png and gui/sprites/container/furnace/lit_progress.png have backgrounds which are the same color as the inventory color. These pixels are redundant since they effectively just clone the background without causing any visual difference (e.g. making any pixels behind them that aren't background-colored appear background-colored when this texture is drawn on top of them), and can be removed from the texture file to make the functionality of these textures clearer.

Blast furnace and smoker textures are similarly affected.

How to fix

Remove these pixels from these textures. Fixed versions are attached - fixing this should be as easy as replacing vanilla's texture files with these.