[docs] Add additional info to MySQL required version

Author: mickhawkins

general/releases/4.5.md

@@ -31,7 +31,7 @@ Moodle supports the following database servers. Again, version numbers are just
 | Database | Minimum version | Recommended |
 | --- | --- | --- |
 | [PostgreSQL](http://www.postgresql.org/) | 13 (increased since Moodle 4.1) | Latest |
-| [MySQL](http://www.mysql.com/) | 8.0 (increased since Moodle 4.1) | Latest |
+| [MySQL](http://www.mysql.com/) | 8.0 (increased since Moodle 4.1). **Note:** If using 8.0 it is recommended to use a supported version of 8.0.x, and avoid version 8.0.0 as it can cause an SQL error due to a reserved work restriction. | Latest |
 | [MariaDB](https://mariadb.org/) | 10.6.7 (increased since Moodle 4.1) | Latest |
 | [Microsoft SQL Server](http://www.microsoft.com/en-us/server-cloud/products/sql-server/) | 2017 | Latest |
 | [Oracle Database](http://www.oracle.com/us/products/database/overview/index.html) | 19c (increased since Moodle 4.3) | Latest |