Added notes on what to set pg-verrsion-force to.

advocacy_docs/supported-open-source/pgbackrest/03-quick_start.mdx

@@ -25,23 +25,25 @@ For **EDB Postgres Advanced Server**:
 
 ```ini
 [global]
-repo1-path=/var/lib/edb/as13/backups
+repo1-path=/var/lib/edb/as15/backups
 
 [demo]
-pg1-path=/var/lib/edb/as13/data
+pg1-path=/var/lib/edb/as15/data
 pg1-user=enterprisedb
 pg1-port=5444
 pg-version-force=15
 ```
 
+The `pg-version-force` value should be set to the same major version number as the server reports when using `show server_version_num;` in PSQL. Only the first two digits are the major version. For example, 15000 is major version 15.
+
 For **PostgreSQL**:
 
 ```ini
 [global]
-repo1-path=/var/lib/pgsql/13/backups
+repo1-path=/var/lib/pgsql/15/backups
 
 [demo]
-pg1-path=/var/lib/pgsql/13/data
+pg1-path=/var/lib/pgsql/15/data
 pg1-user=postgres
 pg1-port=5432
 ```