clean

https://developer.mozilla.org/en-US/docs/Web/CSS/Using_CSS_custom_properties#Custom_property_fallback_values

.three {
  background-color: var(--my-var, var(--my-background, pink));
--border-color: linear-gradient(to top, var(--secondary-color), var(--used-color, white));
}

I'm submitting a...

[x] Feature request

Current behavior

When an element that you expect to be visible is not, the error message is Expected element to be visible.

Expected behavior

The error message would include the matcher used to try to find the element.

Minimal reproduction of the problem with instructions

For bug reports please provide the STEPS TO REPRODUCE

Thanks for so great Tmux plugin.
It would be nice to have a variable to provide separator charchers to make it more configurable.
I'll add few self-explanatory images.

![image](https://user-images.githubusercontent.com/1059539/12