Make double arrows in a square vertical

[FrozenRosesLP]

Hi, in May in this thread I asked the following:

Is there a way to make the double arrow vertical and not tilted to the left in this picture?

Link.

In my thread, Varkor provided me a solution for the problem (editing the code in Notepad) and he mentioned that making the double arrow vertical within quiver is impossible and he suggested I start an issue. Well, here I am, could you make it so that it is possible to make the arrow vertical in quiver?

[varkor]

I expect the most convenient way to support this in the editor is adding an option for each arrow, so that it either points to the arrow centre, or the centre of the source and target. I don't think this would be too difficult to implement.

[varkor]

This feature has been added to quiver in c8962a0 and will be available when I make the next release, which I'm hoping will be soon.