Add size-* shorthand

[thecrypticace]

This PR adds a size-* utility that sets both width and height.

The supported values are the same as the w-* and h-* utilities with the exception of screen units (screen, svh, lvh, dvh, svw, lvw, and dvw).

Now you can write this:

<div class="size-12"></div>

And it will generate the following css:

.size-12 {
  width: 3rem;
  height: 3rem;
}

[ArnaudBarre]

NIT: seems like the alphabetical order was not respected

[yassernasc]

Cool! But why not a shorthand for size-screen?

[DamianGlowala]

@thecrypticace why were the aforementioned exceptions excluded?