Add a test for multidiff with several extensions

[o0Ignition0o]

As a followup to #39 and as explained here It would be nice to add a test with a diff containing several changes to a .rs file and one or more changes to an other file extension.

[oScape]

As I implemented it with the PR #39 I can improve it if you want.

[o0Ignition0o]

Sure, go ahead ! thanks for working on it :D

[ebroto]

Hey @oScape! just a heads-up that there have been a couple changes to the code. There's already a test with serveral extensions but it's only covering newly added files. I think we could add another test for modified files (so files already commited to the repo with changes in the working tree).

Let me know what you think!

[oScape]

Hey @ebroto, I will check it asap, and add the test for midifed files.

[o0Ignition0o]

Take your time, there’s no rush :)