Allow 'gs' to Specify Gather-Scatter Kernel

[radelja]

Overview

This PR updates the command-line parsing to allow both 'gs' and 'sg' to specify the gather-scatter kernel. The argument parsing for JSON files already supports both of these options.

✨ Change Description/Rationale

• Gather-Scatter kernel can now be specified with 'gs' from the command-line
• Closes 🐛 [BUG] - v1.1 gs kernel option is invalid #217

👀 Reviewer Checklist

• All GitHub actions and runners have passed if applicable
• Commits are clean and relevant

✅ PR Checklist

• Remove or update the template boilerplate text
• Commits are relevant and combined where appropriate
• Rebase off spatter-devel
• Reviewers Requested
• Projects associated
• Commits mention issue and/or PR numbers at the bottom of the message
• Relevant issues are linked into the PR
• TODOs are completed
• Reviewer checklist is updated

🚀 TODOs

• No additional TODOs for this PR

📌 Future Work

• No additional future work

[jyoung3131]

This looks good to me, although I wonder if this is confusing for us to allow this? The alternative seems to be to fix the JSON so it only takes one option. What do you think @plavin?