Description

This pull request improves the debugging highlight functionality and fixes an issue where greyed-out highlights were not correctly reset between executions.

When an issue is detected in the code, the extension highlights the affected line in red and displays a descriptive error message explaining the nature of the problem. This visual feedback helps users quickly identify both the location of the error and its underlying cause.

A second part of the implementation concerns the assertion functionality. After an assertion failure, the extension greys out all lines of code that cannot have caused the error. While this behaviour is intended, the greyed-out highlights were previously not cleared when a new execution started. As a result, lines remained greyed out until the editor was closed and reopened.

Overall, the highlighting functionality provides an efficient way to show where an error occurred and what caused it. This change introduces an explicit reset of all greyed-out highlights on launch and restart events, ensuring that each execution starts with a clean editor state.

Fixes #(issue)

Checklist:

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.