investigate if we can switch from black to ruff for formatting

[mattijn]

With the recent introduction of ruff formatter (docs), we can investigate if we can reduce the number of development dependencies by 1.

All of the black related config within pyproject.toml can be rewritten to ruff style config, but we also use black to format code within tools/update_init_file.py (around here), as such:

# Format file content with black
new_file_content = black.format_str("\n".join(new_lines), mode=black.Mode())

I don't think this usage of black is possible with ruff yet, but please correct me if I'm wrong.

(initial attempt in this branch)

[binste]

I'm in favour of moving to ruff! To format strings in the code generation, we can pass the strings through stdin to the ruff format command:

import subprocess

code = """import altair as alt

def some_function():
    d = {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5, 'f': 6, 'g': 7, 'h': 8, 'i': 9, 'j': 10}
    return
    
def another_function():
    c = {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
    return
"""
r = subprocess.run(
    # Name of the file does not seem to matter but ruff requires one
    ["ruff", "format", "--stdin-filename", "placeholder.py"],
    input=code.encode(),
    check=True,
    capture_output=True,
)
print(r.stdout.decode())