chore: update docs for newly allowed param (supabase#20102)

Author: darora

apps/docs/pages/guides/platform/custom-postgres-config.mdx

@@ -27,6 +27,7 @@ The following parameters are available for overrides:
 1. [effective_cache_size](https://postgresqlco.nf/doc/en/param/effective_cache_size/)
 1. [maintenance_work_mem](https://postgresqlco.nf/doc/en/param/maintenance_work_mem/)
 1. [max_connections](https://postgresqlco.nf/doc/en/param/max_connections/)
+1. [max_locks_per_transaction](https://postgresqlco.nf/doc/en/param/max_locks_per_transaction/)
 1. [max_parallel_maintenance_workers](https://postgresqlco.nf/doc/en/param/max_parallel_maintenance_workers/)
 1. [max_parallel_workers_per_gather](https://postgresqlco.nf/doc/en/param/max_parallel_workers_per_gather/)
 1. [max_parallel_workers](https://postgresqlco.nf/doc/en/param/max_parallel_workers/)