Style/ExtraSpacing offense incorrectly triggered with unary plus in argument list

[tilthouse]

Test:

    it 'can handle unary plus in an argument list' do
      source = ['assert_difference MyModel.count, +2 do',
                '  puts "a thing"',
                'end']
      inspect_source(cop, source)
      expect(cop.offenses.size).to eq(0)
    end

Result:

rspec spec/rubocop/cop/style/extra_spacing_spec.rb
Run options:
  include {:focus=>true}
  exclude {:broken=>#<Proc:./spec/spec_helper.rb:32>, :ruby_greater_than_or_equal=>#<Proc:./spec/spec_helper.rb:28>, :ruby_less_than=>#<Proc:./spec/spec_helper.rb:25>, :ruby=>#<Proc:./spec/spec_helper.rb:22>}

All examples were filtered out; ignoring {:focus=>true}

Randomized with seed 30038
..F.................F...................

Failures:

  1) RuboCop::Cop::Style::ExtraSpacing when AllowForAlignment is false can handle unary plus in an argument list
     Failure/Error: expect(cop.offenses.size).to eq(0)

       expected: 0
            got: 1

       (compared using ==)
     Shared Example Group: "common behavior" called from ./spec/rubocop/cop/style/extra_spacing_spec.rb:181
     # ./spec/rubocop/cop/style/extra_spacing_spec.rb:39:in `block (3 levels) in <top (required)>'

  2) RuboCop::Cop::Style::ExtraSpacing when AllowForAlignment is true can handle unary plus in an argument list
     Failure/Error: expect(cop.offenses.size).to eq(0)

       expected: 0
            got: 1

       (compared using ==)
     Shared Example Group: "common behavior" called from ./spec/rubocop/cop/style/extra_spacing_spec.rb:164
     # ./spec/rubocop/cop/style/extra_spacing_spec.rb:39:in `block (3 levels) in <top (required)>'

Finished in 0.06017 seconds (files took 0.34958 seconds to load)
40 examples, 2 failures

Failed examples:

rspec './spec/rubocop/cop/style/extra_spacing_spec.rb[1:2:4]' # RuboCop::Cop::Style::ExtraSpacing when AllowForAlignment is false can handle unary plus in an argument list
rspec './spec/rubocop/cop/style/extra_spacing_spec.rb[1:1:4]' # RuboCop::Cop::Style::ExtraSpacing when AllowForAlignment is true can handle unary plus in an argument list

Randomized with seed 30038

Note: Normally I'd say that the unary plus here is redundant, but in this case we like it for clarity (with assert_difference in this case). In any case, it does not have extra spaces.