Using instead of typedef

Based on !339 (merged)

# with compile_commands.json in cwd
python3 /usr/lib/llvm-12/share/clang/run-clang-tidy.py -header-filter='.*' -checks='-*,modernize-use-using' -fix

Not all typedefs were replaced run-clang-tidy didn't change files whose change resulted in build errors.

I needed to silence warnings in mpi.h for clang to see whether the changes caused any new warnings.