Highlight syntax error location in Editor

[michellabbe]

Is your feature request related to a problem? Please describe

Syntax error like "All collection items must start at the same column" don't provide any hint as to were Portainer is detecting the error.

These are not always obvious to detect and most of the time I need to comment or cut large sections and check if the syntax error disappear or not (then repeat with smaller sections) to figure out where the error is.

Most of the time it ends up being an invisible tab that got inserted by cut & pasting from different sources, or I added some quotes/double quotes (these are often automatically doubled) around strings and I forgot to un-double one of them at beginning or end of line.

Describe the solution you'd like

Apply red highlighting on the line(s) where the syntax error(s) are detected, similar to the blue highlighting of the line where cursor is.
Show tabs as long right arrows (even if pale gray) instead of white spaces so they can easily be spotted when accidentally inserted.

That would make it much easier to detect syntax errors and fix them.

Describe alternatives you've considered

Add some red (dot, vertical line, etc.) in the grey column, next to the line number.

Maybe Portainer could also highlight when single-quotes or double-quotes are doubled and end up with an uneven number in a single line.

Additional context

No response