docs: fix output guardrail step description

[usmanashrf]

Summary

Fixes a copy-paste error in docs/guardrails.md: the first step of “Output guardrails run in 3 steps” said the guardrail “receives the same input passed to the agent,” which contradicts the note and example code. The guardrail actually receives the agent’s output.

What’s changed

Section	Before	After
Bullet 1	“the same input passed to the agent”	“the output produced by the agent”
Adjacent note	“final agent input”	“final agent output”

No code or API behavior is affected—this is documentation only.

Rationale

This clarification prevents confusion for developers writing custom guardrails, aligning the prose with the example signature (def my_guardrail(output: MessageOutput, …)).

Checklist

• Docs build locally (make docs) without warnings
• No other occurrences of the error found via search
• CI passes

Closes #.

[github-actions]

This PR is stale because it has been open for 10 days with no activity.

[github-actions]

This PR was closed because it has been inactive for 7 days since being marked as stale.