Formatter: parenthesize_conditional_expressions preview style

[zanieb]

Implement Black's parenthesize_conditional_expressions style as a preview style in Ruff.

Note: This new style might not be accepted as part of Black's 2024 style guide.

Unformatted:

[
    "____________________________",
    "foo",
    "bar",
    "baz" if some_really_looooooooong_variable else "some other looooooooooooooong value"
]

Formatted (Black stable, Ruff):

[
    "____________________________",
    "foo",
    "bar",
    "baz"
    if some_really_looooooooong_variable
    else "some other looooooooooooooong value",
]

Formatted (Black preview):

[
    "____________________________",
    "foo",
    "bar",
    (
        "baz"
        if some_really_looooooooong_variable
        else "some other looooooooooooooong value"
    ),
]

When it fits again...

Formatter (Ruff, Black stable, Black preview):

[
    "____________________________",
    "foo",
    "bar",
    ("baz" if some_really_looooooooong_variable else "some other loooooooooong value"),
]

Arguably, these should be removed to ensure the formatting is reversible.

[MichaReiser]

We don't plan to implement this preview style as part of Ruff's 2024 style guide because we believe that improving the binary expression formatting solves the problem more holistically. See psf/black#4123 for the details