Fix alignment for Fugitive blame

[ouuan]

By default, Fugitive blame does not have the drop bar, so the line blames are not aligned with the file content.

I use the following config to add a dummy drop bar to fix it:

local default_config = require 'dropbar.configs'.opts

require 'dropbar'.setup {
  general = {
    enable = function(buf, win)
      return default_config.general.enable(buf, win)
        or vim.bo[buf].ft == 'fugitiveblame'
    end,
  },
  bar = {
    sources = function(buf, win)
      if vim.bo[buf].ft == 'fugitiveblame' then
        return {}
      end
      return default_config.bar.sources(buf, win)
    end
  },
}