Review note on availability of recovery crypto units

[Timo-1]

Review the following note Currently, only the us-south and us-east regions support recovery crypto units. Only service instances in these regions can use this command. For more information about supported regions, see [Regions and locations](https://cloud.ibm.com/docs/hs-crypto?topic=hs-crypto-regions).

This note is contained in multiple HPCS documentation pages, e.g. https://cloud.ibm.com/docs/hs-crypto?topic=hs-crypto-initialize-hsm-recovery-crypto-unit and https://cloud.ibm.com/docs/hs-crypto?topic=hs-crypto-recover-master-key-recovery-crypto-unit

But today recovery units can be created for HPCS instances in other locations apparently, at least if one uses Terraform.

Please work with Heidi and the HPCS development team to review and - if required - update this note.

There is also a similar note in the Terraform provider registry https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/hpcs which also needs to be reviewed.

[Timo-1]

please see this issue https://github.com/ibm-cloud-docs/hs-crypto/issues/49

[TiffanyLiIBM]

Move to internal GH board: https://github.ibm.com/ZaaS/zcrypto-backlog/issues/9799