Fix handling of ErlangError when :general key is chardata (elixir-lang#14329)

Author: sabiwara

Diff for: lib/elixir/lib/exception.ex

@@ -2530,7 +2530,7 @@ defmodule ErlangError do
           {:ok, reason, IO.iodata_to_binary([":\n\n" | Enum.map(args_errors, &arg_error/1)])}
 
         general = extra[:general] ->
-          {:ok, reason, ": " <> general}
+          {:ok, reason, ": " <> IO.chardata_to_string(general)}
 
         true ->
           :error

Diff for: lib/elixir/test/elixir/exception_test.exs

@@ -46,6 +46,12 @@ defmodule ExceptionTest do
                {:io, :put_chars, [self(), <<222>>],
                 [error_info: %{module: __MODULE__, function: :dummy_error_extras}]}
              ])
+
+    assert %ErlangError{original: {:failed_load_cacerts, :enoent}, reason: ": this is chardata"} =
+             Exception.normalize(:error, {:failed_load_cacerts, :enoent}, [
+               {:pubkey_os_cacerts, :get, 0,
+                [error_info: %{module: __MODULE__, function: :dummy_error_chardata}]}
+             ])
   end
 
   test "format/2 without stacktrace" do
@@ -1026,4 +1032,8 @@ defmodule ExceptionTest do
   end
 
   def dummy_error_extras(_exception, _stacktrace), do: %{general: "foo"}
+
+  def dummy_error_chardata(_exception, _stacktrace) do
+    %{general: ~c"this is " ++ [~c"chardata"], reason: ~c"this " ++ [~c"too"]}
+  end
 end