Some of the tables of arguments are too complex to be represented by GFM

[atusy]

As @eitsupi has raised issue in REditorSupport/vscode-R#927 , there are some cases where Arguments become VS Code ignores the section if the section remains to be an HTML table due to its complex content. See details in the link.

To avoid this, we need to convert the table to some alternative format.
I would suggest the following style.

### Arguments

#### `Arg1`:

Description of  Arg1

#### `Arg2`:

Description of Arg2.

This may contain multiple paragraphs.

- and some list

or

```
code blocks
```