CodeMirror Error Styling

[ElliotRoe]

Summary
Update the styling of errors in CodeMirror, so it is clearer when there are relevant and time-sensitive errors being displayed.
Requirements

• All runtime errors should be displayed with the error styling until the user has edited that line, then it should change to the warning style
• Errors should track the line that they are on until that line is edited (e.g. if an error is on line 5 and I delete lines 2-4 the error should be on line 2)
• After saving all runtime errors should be styled as warnings

[ElliotRoe]

helpful read: https://lezer.codemirror.net/

[azure-kyuri]

conclusion: ensure that runtime errors are on the line in which it is being tracked. see original ticket above