Fix - key error for a special case such as "뚫리다"

[Min-Ho-Lim]

Summary

Apparently, while I was working on my personal project, I need a simple romanization library for Korean language. And, I found this library. However, I encountered one edge case and this library does not support.

For instance, if a word has a double constant which is "ㅀ" and the next syllable starts with NULL_CONSONANT. It will throw a Key-error as #15 described. It is because there is no logic to handle such case in `pronouncer.py'

So, I created a logic to handle such cases.

Changes

1. Added a logic to handle a special case a syllable has "ㅀ" and the next syllable starts with NULL_CONSONANT
2. Added test_double_consonant_final_and_next_syllable_not_null_initial in test_romanizer.py to prevent this situation in the future.
3. Applied prettier for some files.

Screenshots

Pytest Result

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Name	Status	Preview	Comments	Updated
korean-romanizer	❌ Failed (Inspect)			Jan 17, 2023 at 3:44PM (UTC)

[osori]

Hey! Thank you so much for taking time to fix this bug and providing all the details. I also appreciate the tests you wrote and the linting you applied. Merging this, thanks for your contribution 🥇