Fix flags list formatting

[zekchan]

Description

Fix flags.md formatting

Checklist

• I have added a label to this PR 🏷️
• I have run my changes through Grammarly
• If this requires translations for the moonbeam-docs-cn repo, I have created a ticket for the translations in Jira
• If pages have been moved around, I have created an additional PR in moonbeam-mkdocs to update redirects
• If pages have been moved around, I have run the move-pages.py script to move the pages and update the image paths on the chinese repo
  • After the script has been run, I have created an additional PR in moonbeam-docs-cn
• If images have been added, I have run the compress-images.py script to compress the images.
• If variables (in variables.yml) need to be updated (such as a name change), I have updated the moonbeam-docs-cn repo to use the new variables
• If this page requires a disclaimer, I have added one

Corresponding PRs

Items to be Updated

[eshaben]

Thanks! LGTM!