Fix inspect exception with ANSI enabled

[pnezis]

iex(1)> schema = [foo: [type: :integer]]
[foo: [type: :integer]]
iex(2)> NimbleOptions.validate([transformer: "test"], schema)
{:error,
 #Inspect.Error<
  got FunctionClauseError with message:

      """
      no function clause matching in :lists.do_flatten/2
      """

  while inspecting:

      %{
        message: "unknown options [:transformer], valid options are: [:foo]",
        value: nil,
        key: [:transformer],
        __struct__: NimbleOptions.ValidationError,
        __exception__: true,
        redact: false,
        keys_path: []
      }

  Stacktrace:

    (stdlib 7.3) lists.erl:1322: :lists.do_flatten({:doc_color, [], "\e[0m\e[33m"}, [])
    (stdlib 7.3) lists.erl:1325: :lists.do_flatten/2
    (stdlib 7.3) lists.erl:1323: :lists.do_flatten/2
    (nimble_options 1.1.1) lib/nimble_options/validation_error.ex:56: Inspect.NimbleOptions.ValidationError.inspect/2
    (elixir 1.19.3) lib/inspect/algebra.ex:401: Inspect.Algebra.to_doc_with_opts/2
    (elixir 1.19.3) lib/inspect/algebra.ex:613: Inspect.Algebra.call_container_fun/3
    (elixir 1.19.3) lib/inspect/algebra.ex:590: Inspect.Algebra.container_each/5
    (elixir 1.19.3) lib/inspect/algebra.ex:566: Inspect.Algebra.container_doc_with_opts/6

>}

[whatyouhide]

Great catch! Thank you.