Metallic Bottle: use a slightly darker background color for selections

[eht16]

I just made the background color for selections a little darker so that it is different from the foreground color.

Closes #70.

[eht16]

If there are no objections or improvement suggestions, I would like to merge to this in a week.

[b4n]

I think the gray strings are a bit hard to read on that brown, but I have no opinion apart that the mentioned bug is indeed bad, and if this fixes it, good :)

[eht16]

@b4n they are indeed.
I gave #e4d3c7 it try as a rather lighter brown than before.

This might be better for selection background. Though this makes the braces and the ... in the varags of the function definition harder to read.

I'm really bad at colors :(.

@rovf since you reported it and obviously are using this theme, do you have any preference or a better alternative?

[b4n]

Better, but what about #ebdfd8?

Still not great for readability, but a tad better and the whole theme doesn't focus on contrast it seems.

Not that I care, it's indeed better to get input from actual theme users 🙂

[eht16]

#ebdfd8 seems fine to me.

Let's see what @rovf says.