Macro assert_sometimes_all

macro_rules! assert_sometimes_all {
    ({$($($name:ident: $cond:expr),+ $(,)?)?}, $message:literal$(, $details:expr)?) => { ... };
    ($($rest:tt)*) => { ... };
}

assert_sometimes_all({a: x, b: y, ...}) is similar to assert_sometimes(x && y && ...), except:

• Antithesis has more visibility to the individual propositions.
• There is no short-circuiting, so all of x, y, … would be evaluated.
• The assertion details would be merged with {"a": x, "b": y, ...}.