x_bows.load should return itemstack

[Juraj Vajda]

@Jackknife

I ran across an interesting bug, when using the anvil mod it duplicates the wooden
bow when I go to repair it.

https://content.minetest.net/packages/FaceDeer/anvil/

[Juraj Vajda]

DONE:

• Return itemstack on x_bows.load on_place func

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