🌐 [i18n-KO] Translated main_classes/peft.md (#39515)

* docs: ko: main_classes/peft.md

* feat: nmt draft

* docs: add missing TOC to documentation for `PeftAdapterMixin` section

Added a table of contents (TOC) to the documentation, specifically for the `transformers.integrations.PeftAdapterMixin` section, following the structure and content outlined in [this link](https://huggingface.co/docs/transformers/main/en/main_classes/peft#transformers.integrations.PeftAdapterMixin).

* fix: Improve naturalness of purpose expression in Korean

Changed '관리하기 위한' to '관리할 수 있도록' for more natural Korean expression when describing the purpose of providing functions.

* fix: Simplify plural form and make expression more concise

Changed '~할 수 없기 때문에' to '~할 수 없어' for more concise expression while maintaining clarity.

* fix: Replace technical term '주입' with more natural '적용'

Changed '주입할 수 없어' to '적용할 수 없어' for better readability.
Considered alternatives:

'삽입': Too literal translation of 'inject'
'입력': Could be misunderstood as data input
'통합': Implies merging two systems
'추가': Simple but less precise

'적용' was chosen as it's the most natural and widely used term in Korean technical documentation for this context.

* fix: update toctree path for PEFT to lowercase

Changed the toctree path from 'PEFT' (uppercase) to 'peft' (lowercase) to match the correct directory naming convention and prevent broken links.

* docs: update as per reviewer feedback after rebase

docs/source/ko/main_classes/peft.md

@@ -0,0 +1,23 @@
+<!--Copyright 2024 The HuggingFace Team. All rights reserved.
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+specific language governing permissions and limitations under the License.
+⚠️ Note that this file is in Markdown but contain specific syntax for our doc-builder (similar to MDX) that may not be
+rendered properly in your Markdown viewer.
+-->
+
+# PEFT[[transformers.integrations.PeftAdapterMixin]]
+
+[`~integrations.PeftAdapterMixin`]은 Transformers 라이브러리와 함께 어댑터를 관리할 수 있도록 [PEFT](https://huggingface.co/docs/peft/index) 라이브러리의 함수들을 제공합니다. 이 믹스인은 현재 LoRA, IA3, AdaLora를 지원합니다. 프리픽스 튜닝 방법들(프롬프트 튜닝, 프롬프트 학습)은 torch 모듈에 삽입할 수 없는 구조이므로 지원되지 않습니다.
+
+[[autodoc]] integrations.PeftAdapterMixin
+    - load_adapter
+    - add_adapter
+    - set_adapter
+    - disable_adapters
+    - enable_adapters
+    - active_adapters
+    - get_adapter_state_dict