Add type annotation to make-rust-unicode-data.py

[tamaroning]

Addresses this comment by @CohenArthur

I think this is a very good first implementation of the script :) For future maintainability, I think it would be helpful to add types to the script so we can run it with mypy. But this is already very good, don't change it in this PR

#2425 (comment)

Python code was typechecked with mypy 1.4

gccrs: Type annotation for make-unicode-data.py
gcc/rust/ChangeLog:

	* util/make-rust-unicode.py: Add type annotation

[philberty]

LGTM