round ingredient amounts

[dasnessie]

When scaling a recipe, especially when specifying a yield, the ingredient results can become pretty unreadable.

For example:

$ recipemd -y "4 servings" -i celeriac_mushroom_and_tomato_lasagna.md 
[...]
0.5714285714285714285714285714 small celeriac root
1.714285714285714285714285714 parsnip roots
0.5714285714285714285714285714 tbsp coconut oil, butter, ghee or olive oil
1.142857142857142857142857143 clove garlic
11.42857142857142857142857143 brown mushrooms
142.8571428571428571428571428 g frozen spinach, thawed (fresh is fine too)
11.42857142857142857142857143 cherry tomatoes (or 4 regular tomatoes), sliced

Also, I'm not really sure how to measure out 0.5714285714285714285714285714 tbsp of something. I think rounding to two or three decimals should suffice for most use cases.