Formatting help text (ends of line)

The [command line wiki](https://github.com/commandlineparser/commandline/wiki) shows what help texts look like:

```
yourapp 2.0.201-alpha
[...]
--filename Input filename.

--help Display this help screen.

--version Display version information.
```
Each argument entry is followed by a **double end of line**. I wondered if there is a simple way to get a formatting with single eol, like this `grep` example:

```
Usage: grep [OPTION]... PATTERN [FILE]...
[...]
-E, --extended-regexp PATTERN is an extended regular expression (ERE)
-F, --fixed-strings PATTERN is a set of newline-separated strings
-G, --basic-regexp PATTERN is a basic regular expression (BRE)

```

If I undestand correctly, I'll have to implement [my own help screen](https://github.com/commandlineparser/commandline/wiki/Generating-Help-and-Usage-information#overriding-the-default-behavior) and use `HelpText.RenderUsageText` or `HelpText.RenderUsageTextAsLines` ?

從 HelpText.RenderUsageText 和 HelpText.RenderUsageTextAsLines 開始，這兩個進入點在 issue 中有所提及，並將它們的輸出與 command line wiki 中的範例進行比較。判斷說明項目是否可以使用單一行尾間距，而不取代預設的說明畫面。完成的標準是產生的說明文字支援所要求的 single-EOL 格式，且其輸出已根據範例完成驗證。

由索引模型根據 Issue 內容生成。