Highlight tab bar like status bar

[ingver]

In my case it was of white color, so I decided to add this line

[kstevens715]

I had been using another (similar) color scheme for the last month or so and when I came back to this one today it really stuck out. I saw some activity on this repo this morning and thought it would be a good time to submit an issue for this, but I found this PR.

I might prefer the background be just a bit darker (maybe use the same color as the gutter background?). But this is a big improvement:

Before

After