run pyupgrade over everything

doc/conf.py

pymbolic/__init__.py

pymbolic/algorithm.py

pymbolic/compiler.py

pymbolic/cse.py

pymbolic/functions.py

pymbolic/geometric_algebra/__init__.py

pymbolic/geometric_algebra/mapper.py

pymbolic/geometric_algebra/primitives.py

pymbolic/imperative/statement.py

pymbolic/imperative/transform.py

pymbolic/imperative/utils.py

pymbolic/interop/ast.py

pymbolic/interop/common.py

pymbolic/interop/maxima.py

pymbolic/interop/symengine.py

pymbolic/interop/sympy.py

pymbolic/mapper/__init__.py

pymbolic/mapper/c_code.py

pymbolic/mapper/coefficient.py