Add Information on Armor Overrides in `IClientExtensions`

[ChampionAsh5357]

As the armor overrides are still in an incomplete implementation, I am leaving a note here to add in the information once they have been fully implemented in 1.21.3

• IClientExtensions
  • getHumanoidArmorModel
  • getGenericArmorModel
  • setupModelAnimations
  • renderHelmetOverlay
  • getArmorLayerTintColor
  • getDefaultDyeColor

[ChampionAsh5357]

As a comment for myself, expand off of #171 as the understanding of entity models is important for the custom armor model setup.