Special characters are not being cleaned up in slug

[lucianobargmann]

I wrote this post title: "Recap 2ª Convenção de Lideranças" and slug generated was "recap-2ª-convencao-de-liderancas"

I think the "ª" should be removed from the slug.

U+00AA ª Feminine ordinal indicator
U+00BA º Masculine ordinal indicator 

The suggestion in ticket:9591:47 was to sanitize these symbols to "a" and "o", respectively.

With your example, I get "recap-2a-convencao-de-liderancas" on 3.3.1.

Feel free to reopen if there's still a problem, or if the current sanitization should be reconsidered.