chore: add text highlighting for mention node

[harish-sethuraman]

What does this PR do?

🤖 Generated by Copilot at 8119a6f

Added a blue color to mention nodes in the text editor. This improves the visibility and consistency of mentions in the app.

Related issues

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (non-breaking small changes to existing functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Explanation of the changes

🤖 Generated by Copilot at 8119a6f

• Add text-brand class to mention nodes to make them more visible and consistent (link)

Emoji

👥🎨🆕

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
prerender	✅ Ready (Inspect)	Visit Preview	Sep 7, 2023 6:07am
web	✅ Ready (Inspect)	Visit Preview	Sep 7, 2023 6:07am