Categories with invalid URI character in their name malfunctions

[leonard-IMBERT]

Right now categories can have in their name unicode characters such as 🬃 (https://unicode-table.com/fr/1FB03/).

Because categories are used in the URI in /topic/by/category/:cat, when trying to access the category, the generated URI is /topic/by/category/🬃. When accessing the category it show no topics (even if there are ones)

I suggest that we limit the categories name following the URI rfc for simplicity.

[gr-im]

Yes, it was mentionned here: #23
Since ATM, the owner of categories is @xvw, it is not in "high priority" but I'll keep that in my mind!