fix: emoji in headlines

[KevinGimbel]

This fixes #34

[noverby]

Looks good to me 👍

[KevinGimbel]

Overall it's looking good, but it is kinda hard to test. Sometimes the test_is_emoji_randomized test fails, I think it fails if an emoji contains multiple code points.

In test_is_emoji_fixed a similar problem exists, where some emoji like 🕵️‍♀️ (Female Detective) cannot be used because a single char cannot contain two code points.

I'll give this another nights' sleep and see if I can come up with some real tests.