Use more conventional diff colouring

[hanscauwenbergh]

📌 References

• Issue: None
• Related pull-requests: None

🎩 What is the goal?

Use a more conventional diff colouring in the console message.

📝 How is it being implemented?

Deletions are printed in red, additions in green and if a line was not changed, it's printed in white.

💥 How can it be tested?

Test which matches the expected message when a SnapshotException has been thrown.

👓 Example

When a test fails

[tonilopezmr]

Thanks for contributing 👏👏