add support for barbar buffer picking

[jiyometrik]

the default red might be a bit jarring in barbar.nvim's buffer picking function. can this be changed to another color which fits with the nord theme?

[shaunsingh]

I haven't used barbar, but I'll look into it

[gbprod]

I think i'ts done now : https://github.com/shaunsingh/nord.nvim/blob/master/lua/nord/theme.lua#L150