Unicode confusables characters are removed

[chuckyblack]

https://util.unicode.org/UnicodeJsps/confusables.jsp?a=a&r=None

Current result

from slugify import slugify

assert slugify("𝐚́́𝕒́") == ""

Expected result

from slugify import slugify

assert slugify("𝐚́́𝕒́") == "aa"

Possible solution

I think text = unicodedata.normalize("NFKC", text) should be called before text = unidecode.unidecode(text).

[un33k]

@chuckyblack thanks for reporting it. I have raised a PR, which will normalize the text twice.

#143