Command request: ArrayNewSized, ListNewSized

[JoshuaKGoldberg]

What command(s) would you like to add?

array new sized

list new sized

Creates a new array or list of a fixed size, rather than blank or with existing items.

Sample usage

array new sized : string 5
list new sized : int 10

Why?

I'm working on making a Vector implementation similar to C++'s. There needs to be a way to create an array of a fixed size without knowing the items that will be placed it. #506.