fix(generate): template nested prose with params

[brandtkeller]

Description

Adds a nested parameter to the current replaceParams logic such that we can apply OSCAL prose templating as is used in the OSCAL community against nested items when parameter use is used within a choice selection.

Related Issue

Fixes #779

Relates to #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Schema Updates applied
• Contributor Guide Steps followed