fix: error is always a tuple of two

lib/instructor.ex

@@ -118,6 +118,7 @@ defmodule Instructor do
           {:ok, Ecto.Schema.t()}
           | {:error, Ecto.Changeset.t()}
           | {:error, String.t()}
+          | {:error, any()}
           | Stream.t()
   def chat_completion(params, config \\ nil) do
     params =
@@ -436,7 +437,7 @@ defmodule Instructor do
       {:ok, changeset |> Ecto.Changeset.apply_changes()}
     else
       {:llm, {:error, error}} ->
-        {:error, :adapter_error, error}
+        {:error,  { :adapter_error,error}}
 
       {:valid_json, {:error, error}} ->
         # pass the error as it is to the user consuming API
@@ -445,7 +446,7 @@ defmodule Instructor do
         # So, a smaller model like claude-haiku for subsequent LLM call
         # https://github.com/thmsmlr/instructor_ex/pull/55/files
         Logger.error(error: "Invalid JSON returned from LLM: #{inspect(error)}")
-        {:error, :invalid_json, error}
+        {:error, { :invalid_json, error}}
 
       {:validation, changeset, response} ->
         if max_retries > 0 do