Recode.Task.TagTODO fails with a FunctionClauseError

On a file like:

defmodule MyApp.Error do
  @moduledoc """
  docs
  """
  defexception reason: "undefined error",
               code: nil

  @typedoc """
  type doc
  """
  @type t :: %__MODULE__{reason: any, code: integer() | nil}

  @doc nil
  def message(%{reason: reason}), do: inspect(reason)
end

Recode fails with a FunctionClauseError error:

> mix recode --dry
Read 5 files in 0.06s
....!...................................................!!..
 File: lib/error.ex
[Specs 14/3] Functions should have a @spec type specification.
Execution of the Recode.Task.TagTODO task failed with error:
** (FunctionClauseError) no function clause matching in String.split/3
    (elixir 1.15.7) lib/string.ex:478: String.split(nil, "\n", [])
    (recode 0.7.0) lib/recode/task/tags.ex:98: Recode.Task.Tags.find_tags/2
    (recode 0.7.0) lib/recode/task/tags.ex:54: Recode.Task.Tags.check_tags/3
    (sourceror 0.14.1) lib/sourceror/zipper.ex:380: Sourceror.Zipper.do_traverse/3
    (recode 0.7.0) lib/recode/task/tags.ex:17: Recode.Task.Tags.run/2
    (recode 0.7.0) lib/recode/runner/impl.ex:144: Recode.Runner.Impl.run_task/3
    (elixir 1.15.7) lib/enum.ex:2510: Enum."-reduce/3-lists^foldl/2-0-"/3
    (elixir 1.15.7) lib/task/supervised.ex:101: Task.Supervised.invoke_mfa/2

Execution of the Recode.Task.TagFIXME task failed with error:
** (FunctionClauseError) no function clause matching in String.split/3
    (elixir 1.15.7) lib/string.ex:478: String.split(nil, "\n", [])
    (recode 0.7.0) lib/recode/task/tags.ex:98: Recode.Task.Tags.find_tags/2
    (recode 0.7.0) lib/recode/task/tags.ex:54: Recode.Task.Tags.check_tags/3
    (sourceror 0.14.1) lib/sourceror/zipper.ex:380: Sourceror.Zipper.do_traverse/3
    (recode 0.7.0) lib/recode/task/tags.ex:17: Recode.Task.Tags.run/2
    (recode 0.7.0) lib/recode/runner/impl.ex:144: Recode.Runner.Impl.run_task/3
    (elixir 1.15.7) lib/enum.ex:2510: Enum."-reduce/3-lists^foldl/2-0-"/3
    (elixir 1.15.7) lib/task/supervised.ex:101: Task.Supervised.invoke_mfa/2

 File: lib/fmt.ex
[Specs 15/3] Functions should have a @spec type specification.
[Specs 19/3] Functions should have a @spec type specification.

 File: mix.exs
Updates: 1
Changed by: Format
     ...|
24 24   |      {:freedom_formatter, ">= 2.0.0", only: :dev},
25 25   |      {:recode, "~> 0.6", only: :dev},
   26 + |
26 27   |      # {:dep_from_hexpm, "~> 0.3.0"},
   28 + |
27 29   |      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
28 30   |    ]
     ...|

Executed 60 tasks in 0.02s.
Files: 5 (.ex: 2, .exs: 3)
Updated 1 file
 Found 5 issues
Finished in 0.09s.

I've updated my https://github.com/axelson/recode_formatter_repro with this error case (in https://github.com/axelson/recode_formatter_repro/commit/7a3c5a683a03f188d513494015fefc13e4a29a69)

hrzndhrn / recode

Recode.Task.TagTODO fails with a FunctionClauseError #81