🌐 [i18n-KO] Translated multilingual.mdx to Korean (#23008)

docs: ko: `multilingual.mdx`

Co-authored-by: Hyeonseo Yun <0525_hhgus@naver.com>
Co-authored-by: Gabriel Yang <gabrielwithhappy@gmail.com>
Co-authored-by: Jungnerd <46880056+jungnerd@users.noreply.github.com>
Co-authored-by: Sohyun Sim <96299403+sim-so@users.noreply.github.com>
Co-authored-by: Wonhyeong Seo <wonhseo@kakao.com>

docs/source/ko/_toctree.yml

@@ -42,8 +42,8 @@
   - sections:
     - local: in_translation
       title: (번역중) Use tokenizers from 🤗 Tokenizers
-    - local: in_translation
-      title: (번역중) Inference for multilingual models
+    - local: multilingual
+      title: 다국어 모델 추론하기
     - local: in_translation
       title: (번역중) Text generation strategies
     - sections: