Translate c-api/unicode.po 🤖 (#3413)

Minor translation updates for c-api/unicode.po from English to Spanish:
- UTF-8 representation caching description
- Py_UNICODE removal notice for Python 3.12
- Fixed fuzzy entry formatting

Updated Last-Translator field and Po-Revision-Date.

Closes #3265

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Co-authored-by: Carlos A. Crespo <lvccrespo@gmail.com>

Author: erickisos