Docs: add notice about auto completion min version requirement (#536)

* Docs: add notice about auto completion min version requirement

* Update

* Update

* fix typo
Co-authored-by: NSandy Xu <sandy@juicedata.io>

docs/en/command_reference.md

@@ -47,10 +47,12 @@ COPYRIGHT:
    AGPLv3
 ```
 
-**Note:** If `juicefs` is not placed in your `$PATH`, you should run the script with the path to the script. For example, if `juicefs` is placed in current directory, you should use `./juicefs`. It is recommended to place `juicefs` in your `$PATH` for convenience.
+> **Note**: If `juicefs` is not placed in your `$PATH`, you should run the script with the path to the script. For example, if `juicefs` is placed in current directory, you should use `./juicefs`. It is recommended to place `juicefs` in your `$PATH` for convenience.
 
 ## Auto Completion
 
+> **Note**: This feature requires JuiceFS >= 0.15.0. It is implemented based on `github.com/urfave/cli/v2`. You can find more information [here](https://github.com/urfave/cli/blob/master/docs/v2/manual.md#enabling).
+
 To enable commands completion, simply source the script provided within `hack/autocomplete`. For example:
 
 Bash:
@@ -84,8 +86,6 @@ $ sudo cp hack/autocomplete/bash_autocomplete /etc/bash_completion.d/juicefs
 $ source /etc/bash_completion.d/juicefs
 ```
 
-**Note:** This feature is implemented base on `github.com/urfave/cli/v2`, you can find more information [here](https://github.com/urfave/cli/blob/master/docs/v2/manual.md#enabling).
-
 ## Commands
 
 ### juicefs format

docs/zh_cn/command_reference.md

@@ -47,19 +47,21 @@ COPYRIGHT:
    AGPLv3
 ```
 
-**注意：**如果 `juicefs` 不在 `$PATH` 中，你需要指定程序所在的路径才能执行。例如，`juicefs` 如果在当前目录中，则可以使用 `./juicefs`。为了方便使用，建议将 `juicefs` 添加到  `$PATH` 中。可以参考 [快速上手指南](quick_start_guide.md) 了解安装相关内容。
+> **注意**：如果 `juicefs` 不在 `$PATH` 中，你需要指定程序所在的路径才能执行。例如，`juicefs` 如果在当前目录中，则可以使用 `./juicefs`。为了方便使用，建议将 `juicefs` 添加到  `$PATH` 中。可以参考 [快速上手指南](quick_start_guide.md) 了解安装相关内容。
 
 ## 自动补全
 
+> **注意**：此特性需要使用 0.15.0 及以上版本的 JuiceFS。它基于 `github.com/urfave/cli/v2` 实现，更多信息请参见[这里](https://github.com/urfave/cli/blob/master/docs/v2/manual.md#enabling)。
+
 通过加载 `hack/autocomplete` 下的对应脚本可以启用命令的自动补全，例如：
 
-Bash:
+Bash：
 
 ```bash
 $ source hack/autocomplete/bash_autocomplete
 ```
 
-Zsh:
+Zsh：
 
 ```bash
 $ source hack/autocomplete/zsh_autocomplete
@@ -84,8 +86,6 @@ $ sudo cp hack/autocomplete/bash_autocomplete /etc/bash_completion.d/juicefs
 $ source /etc/bash_completion.d/juicefs
 ```
 
-**注意：**此特性基于 `github.com/urfave/cli/v2` 实现，更多信息请参见[这里](https://github.com/urfave/cli/blob/master/docs/v2/manual.md#enabling)。
-
 ## 命令列表
 
 ### juicefs format