dense usage line

I'd like to list all the options in one line. Is this possible? Manpages call this the synopsis. Some examples:

`du [-H | -L | -P] [-a | -s | -d depth] [-c] [-h | -k | -m | -g] [-x] [-I mask] [file ...]`

```
usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]
[-D [bind_address:]port] [-E log_file] [-e escape_char]
[-F configfile] [-I pkcs11] [-i identity_file]
[-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]
[-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]
[-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]
[user@]hostname [command]
```

```
usage: git [--version] [--help] [-C ] [-c =]
[--exec-path[=]] [--html-path] [--man-path] [--info-path]
[-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]
[--git-dir=] [--work-tree=] [--namespace=]
[]
```

首先定位命令 usage/help 渲染的入口点，并检查当前如何格式化选项定义。将其输出与 issue 中的 synopsis 示例进行比较；完成的标准是支持一种可选的紧凑单行 usage 表示，同时不丢失可用选项。

由索引模型根据 Issue 内容生成。