made mypy happy

mypy.ini

pystencilssfg/configuration.py

pystencilssfg/context.py

pystencilssfg/emitters/cpu/basic_cpu.py

pystencilssfg/kernel_namespace.py

pystencilssfg/source_components/header_include.py

pystencilssfg/source_concepts/cpp/std_mdspan.py

pystencilssfg/source_concepts/cpp/std_vector.py

pystencilssfg/source_concepts/source_objects.py

pystencilssfg/tree/basic_nodes.py

pystencilssfg/tree/conditional.py

pystencilssfg/tree/deferred_nodes.py

pystencilssfg/tree/dispatcher.py

pystencilssfg/tree/visitors.py