🌐 [i18n-KO] Translated biogpt.md to Korean (#33773)

* docs: ko: biogpt.md

* feat: nmt draft

* fix: manual edits

* fix: resolve suggestion

Co-authored-by: Chulhwa (Evan) Han <cjfghk5697@ajou.ac.kr>

---------

Co-authored-by: Chulhwa (Evan) Han <cjfghk5697@ajou.ac.kr>

docs/source/ko/_toctree.yml

@@ -334,8 +334,8 @@
         title: (번역중) BigBird
       - local: in_translation
         title: (번역중) BigBirdPegasus
-      - local: in_translation
-        title: (번역중) BioGpt
+      - local: model_doc/biogpt
+        title: BioGpt
       - local: in_translation
         title: (번역중) Blenderbot
       - local: in_translation