Correct docs on s3-uri-style configuration option
Correct docs on s3-uri-style configuration option

The documentation incorrectly states that the
`<repo>-s3-uri-style` option could be placed in `spec.backups.pgbackrest`,
but in fact it must be placed in `spec.backups.pgbackrest.global`.

This commit modifies the example to show the correct configuration.

CrunchyData/postgres-operator,CrunchyData/postgres-operator