Trim the changelog to the fixes that affect released versions

The nested message pump, the stray wakeup task and the lost out-of-memory errors were all bugs in the await work on this branch, so no released version ever had them and they don't belong in the release notes.

- The nested-callback and late-timeout fixes do affect 0.21.4 and earlier, so they get a line each.

Author: davidtaylorhq

CHANGELOG

@@ -1,6 +1,7 @@
 - Unreleased
   - Add `Context#call_await` and `Context#eval_await`: like `call`/`eval` but block until a returned Promise settles and return the settled value; rejections raise `MiniRacer::RuntimeError`
-  - Preserve timeout, stop, and out-of-memory termination while awaiting Promises and across nested callbacks; prevent late watchdog timeouts from affecting later evaluations
+  - Fix a `call` or `eval` made from a Ruby callback taking the timeout or `stop` meant for the evaluation around it, which then kept running
+  - Fix a timeout that fires just after its own evaluation ends, where it would stop the next evaluation instead
   - Fix a race introduced in 0.21.4 where a request sent right after a nested dispatch (e.g. `perform_microtask_checkpoint` or a nested `call` from an attached callback) could be dropped, deadlocking the context
 
 - 0.21.4 - 24-06-2026