Unknown error output requested issue submission

Precheck

Take a look at the open issues and be sure that your issue is not already covered.
Be sure your versions of Dialyxir and Erlex are up to date.

Environment

Elixir & Erlang/OTP versions (elixir --version):
```
erlang 25.2
elixir 1.13.4-otp-25
```

Which version of Dialyxir are you using? (cat mix.lock | grep dialyxir):

"dialyxir": {:hex, :dialyxir, "1.2.0", "58344b3e87c2e7095304c81a9ae65cb68b613e28340690dfe1a5597fd08dec37", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "61072136427a851674cab81762be4dbeae7679f85b1272b6d25c3a839aff8463"},

Current behavior

Describe current behavior. Include errors, stack traces, and any additional information that might be important here.
```
Please file a bug in https://github.com/jeremyjh/dialyxir/issues with this message.
```

Unknown error occurred: %Protocol.UndefinedError{description: "", protocol: String.Chars, value: {21, 28}}

Legacy warning: /Users/connor/Code/my_app/deps/ctx/src/ctx.erl:21:28: Unknown type timer:time/0

Please file a bug in https://github.com/jeremyjh/dialyxir/issues with this message.

Unknown error occurred: %Protocol.UndefinedError{description: "", protocol: String.Chars, value: {21, 42}}

Legacy warning: /Users/connor/Code/my_app/deps/ctx/src/ctx.erl:21:42: Unknown type timer:time/0

done (warnings were emitted) Halting VM with exit status 2



### Expected behavior
I think it shouldn't be omitting this error.

jeremyjh / dialyxir