Add multiple modalities: tools, functions, json_mode (#218)

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

docs/concepts/patching.md

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+# Patching
+
+Instructor enhances client functionality with three new keywords for backwards compatibility. This allows use of the enhanced client as usual, with structured output benefits.
+
+- `response_model`: Defines the response type for `chat.completions.create`.
+- `max_retries`: Determines retry attempts for failed `chat.completions.create` validations.
+- `validation_context`: Provides extra context to the validation process.
+
+There are three methods for structured output:
+
+1. **Function Calling**: The primary method. Use this for stability and testing.
+2. **Tool Calling**: Useful in specific scenarios; lacks the reasking feature of OpenAI's tool calling API.
+3. **JSON Mode**: Offers closer adherence to JSON but with more potential validation errors. Suitable for specific non-function calling clients.
+
+## Function Calling
+
+```python
+from openai import OpenAI
+import instructor
+
+client = instructor.patch(OpenAI())
+```
+
+## Tool Calling
+
+```python
+import instructor
+from instructor import Mode
+
+client = instructor.patch(OpenAI(), mode=Mode.TOOL_CALL)
+```
+
+## JSON Mode
+
+```python
+import instructor
+from instructor import Mode
+from openai import OpenAI
+
+client = instructor.patch(OpenAI(), mode=Mode.JSON)
+```
+
+### Schema Integration
+
+In JSON Mode, the schema is part of the system message:
+
+```python
+import instructor
+from openai import OpenAI
+
+client = instructor.patch(OpenAI())
+
+response = client.chat.completions.create(
+    model="gpt-3.5-turbo-1106",
+    response_format={"type": "json_object"},
+    messages=[
+        {
+            "role": "system",
+            "content": f"Match your response to this json_schema: \n{UserExtract.model_json_schema()['properties']}",
+        },
+        {
+            "role": "user",
+            "content": "Extract jason is 25 years old",
+        },
+    ],
+)
+user = UserExtract.from_response(response, mode=Mode.JSON)
+assert user.name.lower() == "jason"
+assert user.age == 25
+```