Fix pattern_trit_generator for duplicate letters

[McAJBen]

I'm not too familiar with Python but this is a fix for https://github.com/3b1b/videos/issues/15

The Wordle website uses a different algorithm that first checks for correct letters and will ignore duplicates.

A basic example is the word "ABCDE" and the guess "AAAAA"

• Wordle's algorithm gives the result 🟩⬛⬛⬛⬛
• This repo's algorithm gives the result 🟩🟨🟨🟨🟨

An example for the current day's instance is with the guess "ERROR":

• Wordle's algorithm gives the result 🟩⬛⬛⬛🟩
• This repo's algorithm gives the result 🟩🟨🟨⬛🟩

[atusnial3]

This fix does not work. For example, for guess 'mocks' and answer 'cigar', this yields ⬛⬛⬛⬛⬛, while the actual result should be ⬛⬛🟨⬛⬛.

[McAJBen]

This fix does not work. For example, for guess 'mocks' and answer 'cigar', this yields ⬛⬛⬛⬛⬛, while the actual result should be ⬛⬛🟨⬛⬛.

Hmm, I used the source javascript from Wordle as reference. I tried that test case and I still got ⬛⬛🟨⬛⬛.