🌐 [i18n-KO] Translated perf_train_cpu_many.md to Korean (#24923)

* docs: ko: perf_train_cpu_many.md

* feat: chatgpt draft

* fix: manual edits

* fix: resolve suggestions

Co-authored-by: Jungnerd <46880056+jungnerd@users.noreply.github.com>

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Co-authored-by: Jungnerd <46880056+jungnerd@users.noreply.github.com>

docs/source/ko/_toctree.yml

@@ -115,8 +115,8 @@
       title: (번역중) Training on many GPUs
     - local: perf_train_cpu
       title: CPU에서 훈련
-    - local: in_translation
-      title: (번역중) Training on many CPUs
+    - local: perf_train_cpu_many
+      title: 다중 CPU에서 훈련하기
     - local: in_translation
       title: (번역중) Training on TPUs
     - local: in_translation