Fix a typo

spec/lib/msf/core/payload_generator_spec.rb

@@ -1056,7 +1056,7 @@ RSpec.describe Msf::PayloadGenerator do
         }
       }
       it 'applies the appropriate transform format' do
-        expect(::Msf::Simple::Buffer).to receive(:transform).with(shellcode, 'c', 'buf'. {})
+        expect(::Msf::Simple::Buffer).to receive(:transform).with(shellcode, 'c', 'buf', {})
         payload_generator.format_payload(shellcode)
       end
     end