Fix renamed Postgres process argument variables in tuning docs

ansible-role-postgres v18.6-2 renamed the
`postgres_postgres_process_extra_arguments_*` variables to
`postgres_process_extra_arguments_*`. Its validation now stops the
playbook when an old name is set, so a configuration copied from the
"Tuning PostgreSQL" section fails.

docs/maintenance-postgres.md

@@ -106,12 +106,12 @@ To save disk space in `/tmp`, the dump file is gzipped on the fly at the expense
 
 PostgreSQL can be [tuned](https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server) to make it run faster. This is done by passing extra arguments to the Postgres process.
 
-The [Postgres Ansible role](https://github.com/mother-of-all-self-hosting/ansible-role-postgres) **already does some tuning by default**, which matches the [tuning logic](https://github.com/le0pard/pgtune/blob/master/src/features/configuration/configurationSlice.js) done by websites like https://pgtune.leopard.in.ua/. You can manually influence some of the tuning variables. These parameters (variables) are injected via the `postgres_postgres_process_extra_arguments_default` variable.
+The [Postgres Ansible role](https://github.com/mother-of-all-self-hosting/ansible-role-postgres) **already does some tuning by default**, which matches the [tuning logic](https://github.com/le0pard/pgtune/blob/master/src/features/configuration/configurationSlice.js) done by websites like https://pgtune.leopard.in.ua/. You can manually influence some of the tuning variables. These parameters (variables) are injected via the `postgres_process_extra_arguments_default` variable.
 
 Most users should be fine with the automatically-done tuning. However, you may wish to:
 
-- **adjust the automatically-determined tuning parameters manually**: change the values for the tuning variables defined in the Postgres role's [default configuration file](https://github.com/mother-of-all-self-hosting/ansible-role-postgres/blob/main/defaults/main.yml) (see `postgres_max_connections`, `postgres_data_storage` etc). These variables are ultimately passed to Postgres via a `postgres_postgres_process_extra_arguments_default` variable
+- **adjust the automatically-determined tuning parameters manually**: change the values for the tuning variables defined in the Postgres role's [default configuration file](https://github.com/mother-of-all-self-hosting/ansible-role-postgres/blob/main/defaults/main.yml) (see `postgres_max_connections`, `postgres_data_storage` etc). These variables are ultimately passed to Postgres via a `postgres_process_extra_arguments_default` variable
 
-- **turn automatically-performed tuning off**: override it like this: `postgres_postgres_process_extra_arguments_default: []`
+- **turn automatically-performed tuning off**: override it like this: `postgres_process_extra_arguments_default: []`
 
-- **add additional tuning parameters**: define your additional Postgres configuration parameters in `postgres_postgres_process_extra_arguments_custom`. See `postgres_postgres_process_extra_arguments_default` defined in the Postgres role's [default configuration file](https://github.com/mother-of-all-self-hosting/ansible-role-postgres/blob/main/defaults/main.yml) for inspiration
+- **add additional tuning parameters**: define your additional Postgres configuration parameters in `postgres_process_extra_arguments_custom`. See `postgres_process_extra_arguments_default` defined in the Postgres role's [default configuration file](https://github.com/mother-of-all-self-hosting/ansible-role-postgres/blob/main/defaults/main.yml) for inspiration