`terminal.integrated.shell.linux` setting is deprecated

The `flatpak-warning.txt` provides the following advice:

```
To make the Integrated Terminal automatically use the host system's shell,
you can add this to the settings:

{
"terminal.integrated.shell.linux": "/usr/bin/env",
"terminal.integrated.shellArgs.linux": ["--", "flatpak-spawn", "--host", "bash"]
}
```

To which vs code answers:

> This is deprecated, the new recommended way to configure your default shell is by creating a terminal profile in `#terminal.integrated.profiles.linux#` and setting its profile name as the default in `#terminal.integrated.defaultProfile.linux#`. This will currently take priority over the new profiles settings but that will change in the future.

从 issue 中指定的文件 flatpak-warning.txt 开始，检查有关配置集成终端的建议。更新指南以使用当前的终端配置文件设置，然后验证该警告不再建议使用已弃用的 shell 设置。

由索引模型根据 Issue 内容生成。