Update the 'System or software variable to be replaced by the user' example ad markup used

[yetanothertw]

According to the RH Supplementary Style Guide (https://redhat-documentation.github.io/supplementary-style-guide/#user-replaced-values) this example should be updated to reflect the following guidelines.

Ensure that user-replaced values have the following characteristics:

• Surrounded by angle brackets (< >)
• Separated by underscores (_) for multi-word values
• Lowercase, unless the rest of the related text is uppercase or another capitalization scheme
• Italicized
• If the user-replaced value is referencing a value in code or in a command that is normally monospace, also use monospace for the user-replaced value.

Example AsciiDoc: User-replaced value in a paragraph Create an Ansible inventory file that is named /_<path>_/inventory/hosts.

Suggested change from: Use the following command to roll back a deployment, specifying the deployment name: oc rollback _deployment_. to: Use the following command to roll back a deployment, specifying the deployment name: oc rollback _<deployment>_. alternative suggestion: To roll back a deployment, specify the deployment name: oc rollback _<deployment>_.

[bergerhoffer]

Submitted PR #40 to update example to match the supplementary style guide guidance.