🌐 [i18n-KO] Translated `tasks/summarization.mdx` to Korean (#22783)

docs: ko: tasks/summarization.mdx
Co-authored-by: Hyeonseo Yun <0525_hhgus@naver.com>
Co-authored-by: Jungnerd <46880056+jungnerd@users.noreply.github.com>
Co-authored-by: Wonhyeong Seo <wonhseo@kakao.com>
Co-authored-by: Nayeon Han <nayeon2.han@gmail.com>
Co-authored-by: Gabriel Yang <gabrielwithhappy@gmail.com>
Co-authored-by: Kihoon Son <75935546+kihoon71@users.noreply.github.com>

docs/source/ko/_toctree.yml

@@ -59,8 +59,8 @@
         title: 마스킹된 언어 모델링(Masked language modeling)
       - local: tasks/translation
         title: 번역
-      - local: in_translation
-        title: (번역중) Summarization
+      - local: tasks/summarization
+        title: 요약
       - local: in_translation
         title: (번역중) Multiple choice
       title: (번역중) 태스크별 가이드