Remove wrong argument from spec

The delete function does not take a `should` argument. This commit removes the wrong documentation in the spec.

object_templates/provider_spec.erb

@@ -40,7 +40,7 @@ RSpec.describe Puppet::Provider::<%= provider_class %>::<%= provider_class %> do
  end
  end
 
- describe 'delete(context, name, should)' do
+ describe 'delete(context, name)' do
  it 'deletes the resource' do
  expect(context).to receive(:notice).with(%r{\ADeleting 'foo'})