Don't render sum filter results in scientific notation.

[jg-rp]

This pull request changes the standard sum filter to return a float instead of a BigDecimal when given one or more floats as input, as all standard math filters do.

This is necessary to prevent the result being rendered in scientific notation.

Closes #1725.

[adamklingbaum]

Thank you for identifying and resolving this, @jg-rp. Your fix effectively makes the sum filter's behaviour consistent with other arithmetic operations in Liquid.

It would be great to see additional tests, similar to the ones you added, but with floats as property values (see example below).

Otherwise, this looks great to me.

-Adam

liquid/test/integration/standard_filter_test.rb

Lines 958 to 965 in 0b93182

	def test_sum_with_indexable_map_values
	input = [{ "quantity" => 1 }, { "quantity" => 2, "weight" => 3 }, { "weight" => 4 }]
	assert_equal(0, @filters.sum(input))
	assert_equal(3, @filters.sum(input, "quantity"))
	assert_equal(7, @filters.sum(input, "weight"))
	assert_equal(0, @filters.sum(input, "subtotal"))
	end