This patch adjusts the LGG Color Balance mode to operate in linear space
as opposed to sRGB space, which is more inline with other software and
is more expected to the user.
Versioning was added using pre and post gamma correction, but it is
very slightly different in the blacks because the gamma node only does
power correction.
Pull Request: https://projects.blender.org/blender/blender/pulls/147533
a113121562