Require Delaware married filing separately filers to make the same itemization choice

[martinholmer]

The formula for the de_deduction_indv variable does not correspond to what the form instructions say (namely that married filing separately must make the same itemization decision):

policyengine-us/policyengine_us/variables/gov/states/de/tax/income/deductions/de_deduction_indv.py

Lines 4 to 16 in db2a86c

	class de_deduction_indv(Variable):
	value_type = float
	entity = Person
	label = "Delaware deduction when married couples are filing separately"
	unit = USD
	definition_period = YEAR
	reference = "https://delcode.delaware.gov/title30/c011/sc02/index.html title 30, chapter 11, subchapter II, section 1108"
	defined_for = StateCode.DE
	def formula(person, period, parameters):
	itemized = person("de_itemized_deductions_indv", period)
	standard = person("de_standard_deduction_indv", period)
	return max_(itemized, standard)