Rewrite diff code using Rich

The code in diff.py is pretty much the final location in Ward that isn’t using Rich for terminal output. We should update it to use Rich, which should also allow us to more easily add test coverage around this area.

I’ve put this as a “Good First Issue” because the diff code is fairly de-coupled from the rest of Ward.

[willmcgugan]

Happy to help! I did have an idea to implement a diff renderable, but it wouldn’t happen for a while.

You probably want to use the console protocol to create a renderable Diff object. So you create an instance, and then print it with the console. Something like this:

my_diff = Diff(code)
console.print(my_diff)

The existing renderables all use this protocol. See the code here, in particular syntax.py which you will probably want to use as a reference.

Mention me if you have any questions…

[alanbato]

I’ll try to tackle this 😃 Any pointers are appreciated.