Change baby piglin jockey spawn equipment to include a spear

Baby piglins have a low chance of existing (5%) and a low chance of becoming a jockey (10%). Altering these rates and the chance for baby piglins to spawn with equipment like spears would give players an exciting new opportunity for battle in the nether. Baby Hoglins should also be prevented from growing up as long as they have a rider. Baby hoglins should have a tweak to their intelligence so they don't smother their riders in one block spaces. Making this modest change to an existing feature would flesh out this drop nicely.