show changed cells visually

[jouve]

Feature

the same vscode shows changed rows in text file by adding a marker to the line, it would be nice if edit-csv did something similar.

Possible suggestions:

• add a marker like vscode code
• show the cell in a different color
• show the cell in bold/italic

[janisdd]

Can you show me a picture of how "vscode shows changed lines"? Do you mean the indicators when the file is in a git repository?

Anyway, interesting idea. This requires a copy of the original table to be kept in memory (and after each save).
This is because the user can do the following: Initial value -> change -> back to initial value.

The undo/redo data is not sufficient to recognise this and false positives would occur.

I think this would be best as an option for the extension as it might distract the normal user.
As for the colors, we could use green (new) and blue (change). I think it would be a good idea to color the background of a cell. Currently the search function also uses this approach to color matching cells.