Fix content for Markdown preview when no value

[chao-xian]

Before the message to the user was specific to the Guidance page.

Before

After

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
20.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

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[hannahkc]

Content is good!

[thomasiles]

looks good 🏅