Update documentation with new configuration setting

[mzhou0]

Description

Update the SUPReMM documentation with a new configuration setting, hyperthreaded_ratio.

Motivation and Context

In supremm/#248, an optional configuration setting hyperthreaded_ratio is added that specifies the number of hyperthreaded cores per physical core. This PR updates the documentation with descriptions about the new setting.

Tests performed

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project as found in the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.