Describe the issue:
The Ceph 4.x documentation section titled "4.8. Deploying OSDs with different hardware on the same host" has incorrect syntax and a typo.

Describe the task you were trying to accomplish:
Configuring an SSD tier and an HDD tier on a single Ceph cluster using ceph-ansible

Suggestions for improvement:
The documentation has this stanza which has erroneous formatting and a typo that will cause a failure:

create_crush_tree: true
crush_rule_config: true
crush_rules:
  name: HDD
    root: default
    type: host
    class: hdd
    default: true
  name: SDD
    root: default
    type: host
    class: sdd
    default: true

This is the correct formatting of the "crush_rules" section and using a valid device class (s/sdd/ssd/):

create_crush_tree: true
crush_rule_config: true
crush_rules:
  - name: HDD
    root: default
    type: host
    class: hdd
    default: true
  - name: SDD
    root: default
    type: host
    class: ssd
    default: true

Document URL:
https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/4/html-single/installation_guide/index#deploying-osds-with-different-hardware-on-the-same-host_install

Chapter/Section Number and Title:
4.8. Deploying OSDs with different hardware on the same host

Product Version:
Ceph 4.x

Environment Details:
Environments with two tiers of disks.

Any other versions of this document that also needs this update:
Probably all of the Ceph 4 versions.

Additional information:
none