New Rule Suggestion / Rule amendment - in response to #903

In Issue #903 the rule in my opinion correctly throws on a += for simple defined arrays using the $var = @() method of defining an array to the var variable

I would suggest that a new rule is created that correctly identifies this method as being an expensive action and that a recommendation to use a fully defined Array collection would be a better suggestion, initially suggesting using a System.Collections.ArrayList

This rule should look for both @() & += and suggest converting these calls better scripting practices

まず issue #903 と、配列に対する += を処理する既存のルールを読みます。アナライザーが @() と += の両方をどのように認識すべきかを判断し、完全に定義されたコレクション（最初は System.Collections.ArrayList）が提案されることを確認するために必要な推奨事項とテストを定義します。