🌐 [i18n-KO] Translated `trainer.md` to Korean (#32260)
* docs: ko: ko-trainer
* feat: nmt draft
* fix: manual edits
* fix: manual edits
* fix: glossary
* fix: glossary
* Apply suggestions from code review
Co-authored-by: Jinuk <45095330+JinukHong@users.noreply.github.com>
Co-authored-by: SeongWooChoi <46990061+nuatmochoi@users.noreply.github.com>
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Co-authored-by: Jinuk <45095330+JinukHong@users.noreply.github.com>
Co-authored-by: SeongWooChoi <46990061+nuatmochoi@users.noreply.github.com>
