InvalidNullError docs for value attribute

[ravangen]

Describe the bug

When can InvalidNullError return ExecutionError for value?

graphql-ruby/lib/graphql/invalid_null_error.rb

Lines 12 to 13 in c2dedb0

	# @return [nil, GraphQL::ExecutionError] The invalid value for this field
	attr_reader :value

Steps to reproduce

Looks to only be set here

graphql-ruby/lib/graphql/execution/interpreter/runtime.rb

Lines 469 to 476 in c2dedb0

	case value
	when nil
	if is_non_null
	set_result(selection_result, result_name, nil, false, is_non_null) do
	# When this comes from a list item, use the parent object:
	parent_type = selection_result.is_a?(GraphQLResultArray) ? selection_result.graphql_parent.graphql_result_type : selection_result.graphql_result_type
	# This block is called if `result_name` is not dead. (Maybe a previous invalid nil caused it be marked dead.)
	err = parent_type::InvalidNullError.new(parent_type, field, value)

Expected behavior

 # @return [nil] The invalid value for this field 
 attr_reader :value 

At which point, we might as well drop the attribute entirely?

[rmosolgo]

👍 LGTM. Probably the implementation changed over the years, but that (nine-year-old!) doc comment wasn't updated.

[ravangen]

Opened #5256 to resolve this feedback