new feature: unusable parameters warning

Problem to be solved

PowerShell (theoretically) supports parameters whose name can consist only from numbers. For example, this is a valid declaration:

function p1([switch]$1) {if ($1) {'Yes'} else {'No'}}

However, it is very hard to call properly this script. This one will not work:

PS /home/iiric> p1
No
PS /home/iiric> p1 -1
No

This is because parser will think -1 is a negative number rather than a parameter name in this instance.

Proper (=hard) way would be to use splatting.

$params = @{ '1' = $true }
PS> p1 @params
Yes

Generally, this is not the only example of such unusable parameters. See response by @vexx32 in PowerShell repo issue.

Summary of the new feature

Create a PSSA rule that warns when such parameters are created, so users are aware ahead of time that they're making parameters that they won't be able to refer to.

まず既存の PSScriptAnalyzer ルールと、それらが診断をどのように報告するかを確認し、次にリンク先の PowerShell issue を調べて、使用できないと見なされるケースを確認します。パラメーターを通常の方法で参照できない場合に、数値のみのパラメーター（$1 など）も含めて、アナライザーが警告すれば完了です。