Display "completions not supported" for resource templates which do not support completions.

[balajmarius]

Motivation and Context

This adds the functionality requested #458 and a small dark screen fix.

How Has This Been Tested?

Added combobox.test.jsx.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[cliffhall]

Hi @balajmarius! Thanks for this. Could you add a screenshot of the implementation?

The screenshot in #458 shows the id field with a dropdown that only displays the message that completions are not supported when you click it. That doesn't seem right. I think that the entire component should be replaced with the message instead. No need to click a dropdown in order to find out that it isn't supported.

[balajmarius]

Hi @cliffhall,

Thanks for the feedback!

You're right, my current implementation places the message inside the dropdown component. I'll update the PR in the next few days to replace the entire component with the message instead.