Make Giant's Belt Build out of 2x Ruby Crystals

For almost all defensive items, a Giant's Belt only builds into armor items and a Ruby Crystal only builds into magic resist items (I think Ohmwrecker is the only exception to this).

This can be punishing to tanks who typically build their first defensive item earlier in a game than other rolls when it may not yet be apparent who the biggest damage threat on the enemy team is.

Making Giant's Belt build out of two Ruby Crystals (plus a combine cost of 200 gold, keeping the total price the same) smooths out tank builds and gives tanks more early/mid game choices.