docs: add docstring for parameter session in run, run_sync and run_streamed functions (openai#1739)

Author: LokinDev

src/agents/run.py

@@ -272,6 +272,7 @@ async def run(
                 We recommend only using this if you are exclusively using OpenAI models;
                 other model providers don't write to the Conversation object,
                 so you'll end up having partial conversations stored.
+            session: A session for automatic conversation history management.
         Returns:
             A run result containing all the inputs, guardrail results and the output of the last
             agent. Agents may perform handoffs, so we don't know the specific type of the output.
@@ -329,6 +330,7 @@ def run_sync(
             previous_response_id: The ID of the previous response, if using OpenAI models via the
                 Responses API, this allows you to skip passing in input from the previous turn.
             conversation_id: The ID of the stored conversation, if any.
+            session: A session for automatic conversation history management.
         Returns:
             A run result containing all the inputs, guardrail results and the output of the last
             agent. Agents may perform handoffs, so we don't know the specific type of the output.
@@ -383,6 +385,7 @@ def run_streamed(
             previous_response_id: The ID of the previous response, if using OpenAI models via the
                 Responses API, this allows you to skip passing in input from the previous turn.
             conversation_id: The ID of the stored conversation, if any.
+            session: A session for automatic conversation history management.
         Returns:
             A result object that contains data about the run, as well as a method to stream events.
         """