`MPI_Abi_set_fortran_booleans` should take `const void *` argments

[eschnett]

The function MPI_Abi_set_fortran_booleans is declared as

int MPI_Abi_set_fortran_booleans(int logical_size, void *logical_true, void *logical_false)

Since the logical_true and logical_false parameters are inputs, they should be declared as const void *.