Apply changes suggested in PR

Author: Akshay Gadhave

guides/common/modules/proc_upgrading-postgresql-on-the-external-database-system.adoc

@@ -10,8 +10,9 @@ Upgrade the external database to PostgreSQL 13
 endif::[]
 
 .Procedure
-. Backup the `var/lib/pgsql/data/postgresql.conf` and `/var/lib/pgsql/data/pg_hba.conf` files.
+. Back up the `var/lib/pgsql/data/postgresql.conf` and `/var/lib/pgsql/data/pg_hba.conf` files.
 . Follow the instructions in {RHELDocsBaseURL}8/html/deploying_different_types_of_servers/using-databases#fast-upgrade-using-the-pg_upgrade-tool_migrating-to-a-rhel-8-version-of-postgresql[Fast upgrade using the pg_upgrade utility] in _{RHEL}{nbsp}8 Deploying different types of servers_ to upgrade the external database.
++
 Instead of enabling the `postgresql:13` module, switch to the module:
 +
 [options="nowrap", subs="+quotes,verbatim,attributes"]