docs: clarify drainBatchSize changeset wording

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: d-cs

.changeset/mollifier-drain-batch-size.md

@@ -2,4 +2,4 @@
 "@trigger.dev/redis-worker": patch
 ---
 
-`MollifierDrainer` accepts a `drainBatchSize` option (default 1) that lets a single env drain at full `concurrency`-parallelism per tick.
+`MollifierDrainer` accepts a `drainBatchSize` option (default 1) that controls how many entries are popped per env per tick — in-flight handlers remain capped by the global `concurrency`.