Use SWIG_AppendOutput to support swig 4.3

Use SWIG_AppendOutput to support swig 4.3

Swig has changed language specific AppendOutput functions. But helper
macro SWIG_AppendOutput remains unchanged. Use that everywhere instead
of SWIG_Python_AppendOutput, which would require one extra parameter
since swig 4.3.0.

https://github.com/swig/swig/blob/v4.3.0/CHANGES.current#L376
https://github.com/swig/swig/issues/2905