[Feature Request]: Marking a non-existent line in the stream with red

### What would you like to happen?

Following the String Operations transformation where a non-existent line is highlighted in red, would it be possible to add this to other transformations?

### Issue Priority

Priority: 3

### Issue Component

Component: Hop Gui

Start in Hop Gui by examining how the String Operations transformation highlights a non-existent stream line in red. Identify which other transformations should receive equivalent marking; done means those transformations visibly mark non-existent lines consistently.

Written by the indexing model from the issue text.