Docs: Add note about docker volume deletion in README files，will be more novice-friendly (#5133)

### What problem does this PR solve?


Docs: Add note about docker volume deletion in README files
refer to this question:
https://github.com/infiniflow/ragflow/issues/5132
### Type of change

- [x] Documentation Update

---------

Co-authored-by: wenju.li <wenju.li@deepctr.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

README.md

@@ -252,6 +252,7 @@ RAGFlow uses Elasticsearch by default for storing full text and vectors. To swit
    ```bash
    $ docker compose -f docker/docker-compose.yml down -v
    ```
+   Note: `-v` will delete the docker container volumes, and the existing data will be cleared.
 
 2. Set `DOC_ENGINE` in **docker/.env** to `infinity`.
 

README_ja.md

@@ -219,6 +219,7 @@ RAGFlow はデフォルトで Elasticsearch を使用して全文とベクトル
    ```bash
    $ docker compose -f docker/docker-compose.yml down -v
    ```
+   Note: `-v` は docker コンテナのボリュームを削除し、既存のデータをクリアします。
 2. **docker/.env** の「DOC \_ ENGINE」を「infinity」に設定します。
 
 3. 起動コンテナ：

README_ko.md

@@ -220,6 +220,7 @@ RAGFlow 는 기본적으로 Elasticsearch 를 사용하여 전체 텍스트 및
    ```bash
    $docker compose-f docker/docker-compose.yml down -v
    ```
+   Note: `-v` 는 docker 컨테이너의 볼륨을 삭제하고 기존 데이터를 지우며, 이 작업은 컨테이너를 중지하는 것과 동일합니다.
 2. **docker/.env**의 "DOC_ENGINE" 을 "infinity" 로 설정합니다.
 3. 컨테이너 부팅:
    ```bash

README_pt_br.md

@@ -240,7 +240,7 @@ O RAGFlow usa o Elasticsearch por padrão para armazenar texto completo e vetore
    ```bash
    $ docker compose -f docker/docker-compose.yml down -v
    ```
-
+   Note: `-v` irá deletar os volumes do contêiner, e os dados existentes serão apagados.
 2. Defina `DOC_ENGINE` no **docker/.env** para `infinity`.
 
 3. Inicie os contêineres:

README_tzh.md

@@ -227,6 +227,7 @@ RAGFlow 預設使用 Elasticsearch 儲存文字和向量資料. 如果要切換
    ```bash
    $ docker compose -f docker/docker-compose.yml down -v
    ```
+   Note: `-v` 將會刪除 docker 容器的 volumes，已有的資料會被清空。
 
 2. 設定 **docker/.env** 目錄中的 `DOC_ENGINE` 為 `infinity`.
 

README_zh.md

@@ -228,6 +228,7 @@ RAGFlow 默认使用 Elasticsearch 存储文本和向量数据. 如果要切换
    ```bash
    $ docker compose -f docker/docker-compose.yml down -v
    ```
+   Note: `-v` 将会删除 docker 容器的 volumes，已有的数据会被清空。
 
 2. 设置 **docker/.env** 目录中的 `DOC_ENGINE` 为 `infinity`.