doc:  PG 13 relnotes:  fix link for grouping sets hash overflow
Use "guc-enable-groupingsets-hash-disk".
Reported-by: TAKATSUKA Haruka
Discussion:
Backpatch-through: master
@@ -645,7 +645,7 @@ Author: Jeff Davis <jdavis@postgresql.org>
<para>
Previously, hash aggregation was avoided if it was expected to use
more than <xref linkend="guc-work-mem"/> memory. This is controlled
- by <xref linkend="guc-enable-hashagg-disk"/>.
+ by <xref linkend="guc-enable-groupingsets-hash-disk"/>.
</para>
</listitem>
