Possibly outdated claim about number of Postgres metrics generated per relation

[patbl]

This comment claims that each Postgres relation that metrics are enabled for generates "10 + 10 per index" metrics:

integrations-core/postgres/datadog_checks/postgres/data/conf.yaml.example

Line 128 in 1b6118d

## Each relation generates many metrics (10 + 10 per index).

That was probably right when the comment was written, but I think there are more now. Here are the ones that seem to be defined in RELATION_METRICS:

integrations-core/postgres/datadog_checks/postgres/relationsmanager.py

Line 247 in 9b20f7c

RELATION_METRICS = [LOCK_METRICS, REL_METRICS, IDX_METRICS, SIZE_METRICS, STATIO_METRICS]

postgresql.locks
postgresql.autoanalyzed
postgresql.live_rows
postgresql.vacuumed
postgresql.rows_deleted
postgresql.autovacuumed
postgresql.rows_updated
postgresql.seq_rows_read
postgresql.seq_scans
postgresql.analyzed
postgresql.index_rel_rows_fetched
postgresql.rows_inserted
postgresql.rows_hot_updated
postgresql.index_rel_scans
postgresql.dead_rows
postgresql.index_rows_read
postgresql.index_scans
postgresql.index_rows_fetched
postgresql.index_size
postgresql.total_size
postgresql.table_size
postgresql.toast_index_blocks_read
postgresql.toast_index_blocks_hit
postgresql.toast_blocks_read
postgresql.index_blocks_read
postgresql.heap_blocks_read
postgresql.index_blocks_hit
postgresql.toast_blocks_hit
postgresql.heap_blocks_hit

That's 29. Maybe the comment could be updated to say "at least" the whatever the current figures are.