pyproject.toml: Make ruff aware of MicroPython builtins.

This commit updates the project-wide configuration for `ruff`, in order
to not let it flag usages of MicroPython-specific types and keywords
when performing code checks.

The tool currently has an exceptions list that covers almost all Python
code that ships with MicroPython, however code placed in
`ports/<port>/modules` (or elsewhere) by users for customisation
purposes will end up raising errors for otherwise valid
MicroPython-flavoured code.

Changes only let `ruff` assume that it knows about the existence of the
`micropython` module (used without an initial import) for decorators
(eg. `native`, `viper`, `asm_...`, etc.), Viper pointer types (`ptr`,
`ptr8`, `ptr16`, `ptr32`), and the `const` constructor.

For code that is placed elsewhere, these rules won't apply, so it might
be an option to add further configuration instruciton in the "getting
started" documentation files.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

Author: agatti

pyproject.toml

@@ -34,6 +34,7 @@ extend-exclude = [
 extend-include = ["tools/cc1"]
 line-length = 99
 target-version = "py38"
+builtins = ["ptr", "ptr8", "ptr16", "ptr32", "uint", "micropython", "const"]
 
 [tool.ruff.lint]
 exclude = [  # Ruff finds Python SyntaxError in these files