Performed using https://github.com/ilevkivskyi/com2ann
This has no actual effect on the codebase as type checkers (still)
support both and negligible effect on runtime performance since
__future__ annotations ameliorates that. Technically, the bytecode would
be bigger for non function-local annotations, of which we have many
either way.
So if it doesn't really matter, why do a large-scale refactor? Simple:
because people keep wanting to, but it's getting nickle-and-dimed. If
we're going to do this we might as well do it consistently in one shot,
using tooling that guarantees repeatability and correctness.
Repeat with:
```
com2ann mesonbuild/
```
Inside of mesonbuild.ast.* we can and should import from .foobar, rather
than importing from .__init__'s re-exported version of that object.
Failing to do so results in an extremely brittle codebase where simply
changing the order of lines in __init__.py can result in ImportError.
Eli Schwartz