This should be reviewed first: #14465

fixed #14469

What it does

Allows comments in prompt templates

• Comments must start in the first line only, but can then be multile lines
• Comments are {{!-- comment --}}

How to test

There are automated tests.

Manual test:
Add comments and observe no effect on:

• LLM requests
• Variable detection in the AI configuration view

Check comments are highlighted correctly in the prompt editor:

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines