def prepend_runtimepath(dir)
      dir_path = Path.new(dir)
      runtimepath = Path.new(echo('&runtimepath'))
      command("set runtimepath=#{dir_path},#{runtimepath}")
    end
def prepend_runtimepath(dir)
      dir_path = Path.new(dir)
      runtimepath = Path.new(echo('&runtimepath'))
      command("set runtimepath=#{dir_path},#{runtimepath}")
    end
Public: Prepends a directory to Vim's runtimepath. Use this instead of
 #append_runtimepath to give the directory higher priority when Vim
 runtime's a file.

 dir - The directory added to the path

 Returns nothing.