Update dark-ardour.colors - patch selector knobs unnamed >> lighter

[cooltehno]

This PR changes unnamed knobs fill in the midi patch selector from almost indistinguishable dark to the intelligible light.

[cooltehno]

I suppose I had overloaded the illustration with my GIF enthusiasm// So here's a simple comparative picture (left side - current, right-PR). I mean in current stage unnamed knobs are the same as named:

[cooltehno]

@x42 "some that do have MIDNAM files have valid responses to unnamed ones" A... didn't know. No problem)) You're master! ))

[pauldavisthefirst]

For the reasons outlined by x42, I think we don't want this change.