Clarify show deployment docs

[nick-benoit]

Description

Clarifies show docs per discussion in this issue.

Related Issues

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improves code quality but has no user-facing effect)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Readiness Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

[github-actions]

🔍 Preview links for changed docs

• docs/reference/ecctl_deployment_show.md