Fix: Use plenary.filetype.detect and remove own filetype detect (#326)

requires newest plenary.nvim version or you will have a bad day

lua/telescope/path.lua

@@ -56,22 +56,6 @@ path.normalize = function(filepath, cwd)
   return filepath
 end
 
-path.read_last_line = function(filepath)
-  local fd = vim.loop.fs_open(filepath, "r", 438)
-  if fd == nil then return '' end
-  local stat = assert(vim.loop.fs_fstat(fd))
-  local data = ''
-  local index = stat.size - 2
-  while true do
-    local char = assert(vim.loop.fs_read(fd, 1, index))
-    if char == '\n' then break end
-    data = char .. data
-    index = index - 1
-  end
-  assert(vim.loop.fs_close(fd))
-  return data
-end
-
 path.read_file = function(filepath)
   local fd = vim.loop.fs_open(filepath, "r", 438)
   if fd == nil then return '' end