Simplify "fold_array" macro

[Besler]

• Macro now applies to arbitrary dimensions
• Removes the reference format of the macro (&$method:ident, { $x:expr }). Tests passed fine, I couldn't find anywhere it was needed.

Macro expand to an inverted composition:

Before

#[inline]
fn sum(self) -> S
where
    S: Add<Output = S>,
{
    self.x.add(self.y).add(self.z)
}

Now

#[inline]
fn sum(self) -> S
where
    S: Add<Output = S>,
{
    self.x.add(self.y.add(self.z))
}

[bors[bot]]

Configuration problem: bors.toml: not found