add slotted runtime note

Author: JPryce-Aklundh

modules/ROOT/pages/subqueries/subqueries-in-transactions.adoc

@@ -543,6 +543,9 @@ If the transaction still fails after the maximum duration, the failure is handle
 `ON ERROR RETRY` increases query robustness by handling transient errors without manual intervention.
 It is particularly suitable for xref:subqueries/subqueries-in-transactions.adoc#concurrent-transactions[concurrent transactions], reducing the likelihood of xref:subqueries/subqueries-in-transactions.adoc#deadlocks[deadlocks].
 
+[NOTE]
+Queries using `ON ERROR RETRY` can currently only use the xref:planning-and-tuning/runtimes/concepts.adoc#runtimes-slotted-runtime[slotted runtime].
+
 .Basic retry with default duration
 =====