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

先閱讀 issue #903 以及處理陣列 += 的現有規則。確定 analyzer 應如何識別 @() 和 +=，然後定義所需的 recommendation 和 tests，以確認會建議完全定義的 collections，起初為 System.Collections.ArrayList。