Some unicode hashtags federate badly

[timorl]

Steps to reproduce the problem

1. Toot on a Mastodon instance with a unicode hashtag like #ć.
2. Get the post at an Akkoma instance.
3. Look at the hashtag #ć on that instance.

Expected behaviour

The post appears there

Actual behaviour

The post is not there, but it is under #c

Detailed description

Hashtags get "normalized" to ASCII(?) in some instances. Then during federation only the "normalized" variant gets sent, instead of the actual hashtag. See https://akkoma.dev/AkkomaGang/akkoma/issues/568 for some more technical details.

It would be nice to not perform this "normalization" at all, since 'ć' and 'c' are barely connected distinct letters, but failing that at least federating the actual hashtag would be preferable.

Specifications

I was on the Akkoma end of this interaction, but there were a couple Mastodon instances involved, and all had the problem.