docs: revert input_guardrails.py docstring changes

Author: RVV-karma

examples/agent_patterns/input_guardrails.py

@@ -17,18 +17,14 @@
 """
 This example shows how to use guardrails.
 
-Guardrails are checks that run either in parallel with the agent or before the agent starts.
+Guardrails are checks that run in parallel to the agent's execution.
 They can be used to do things like:
 - Check if input messages are off-topic
 - Check that input messages don't violate any policies
 - Take over control of the agent's execution if an unexpected input is detected
 
 In this example, we'll setup an input guardrail that trips if the user is asking to do math homework.
 If the guardrail trips, we'll respond with a refusal message.
-
-By default, guardrails run in parallel with the agent for better latency.
-You can set run_in_parallel=False to run the guardrail before the agent starts,
-which saves token costs if the guardrail fails (the agent never starts).
 """