Update database_maintenance_tools.md (#15083)

* Update database_maintenance_tools.md

Included a blog post by Jackson Chen, which DID work when I followed it to perform Matrix Synapse Maintenance, versus the 2020 blog post by Victor Berger, which DID NOT work when performining maintenance.

* Update database_maintenance_tools.md

* Rephrasing

Author: jahway603

changelog.d/15083.doc

@@ -0,0 +1 @@
+Refer to a more recent blog post on the [Database Maintenance Tools](https://matrix-org.github.io/synapse/latest/usage/administration/database_maintenance_tools.html) page. Contributed by @jahway603.

docs/usage/administration/database_maintenance_tools.md

@@ -1,4 +1,4 @@
-This blog post by Victor Berger explains how to use many of the tools listed on this page: https://levans.fr/shrink-synapse-database.html
+_This [blog post by Jackson Chen](https://jacksonchen666.com/posts/2022-12-03/14-33-00/) (Dec 2022) explains how to use many of the tools listed on this page. There is also an [earlier blog by Victor Berger](https://levans.fr/shrink-synapse-database.html) (June 2020), though this may be outdated in places._
 
 # List of useful tools and scripts for maintenance Synapse database:
 
@@ -15,4 +15,4 @@ The purge history API allows server admins to purge historic events from their d
 Tool for compressing (deduplicating) `state_groups_state` table.
 
 ## [SQL for analyzing Synapse PostgreSQL database stats](useful_sql_for_admins.md)
-Some easy SQL that reports useful stats about your Synapse database.
+Some easy SQL that reports useful stats about your Synapse database.