Soften the async-tool changelog entry

The guidance makes the model likelier to deliver a late result on its
own; it does not guarantee it.

Author: kompfner

changelog/+async-tool-own-run.fixed.md

@@ -1 +1 @@
-- Fixed the async-tool guidance given to LLMs (`ASYNC_TOOL_INSTRUCTIONS` and the final-result message) so a result that lands after the model has already answered the user is delivered on its own, without the model repeating its previous reply first. The guidance now distinguishes a result arriving while the user has an unanswered request from one arriving on a run of its own.
+- Tweaked the async-tool guidance given to LLMs (`ASYNC_TOOL_INSTRUCTIONS` and the final-result message) so a result that lands after the model has already answered the user is more reliably delivered on its own, without the model repeating its previous reply first.