feat: truncation of winbar when there is not enough room

[utilyre]

Reference: #16

[olimorris]

All seems to be working great. I keep get an annoying barbecue: truncation methods other that 'simple' are not supported yet prompt on startup though

[utilyre]

Yeah I didn't want to have the default method be simple. But since it was the only one that's been implemented, I left a notification there and made it set the method to simple temporarily. It's going to be removed once merged.

Here's a workaround though

require'barbecue'.setup({
  truncation = {
    method = 'simple'
  }
})