support for optional #[inline]

[snaar]

Would it be possible to support adding #[inline] to the generated fn signatures? I.e. for example have:

#[inline]
fn $ops_fn(self, $rhs_i: $rhs) -> Self::Output {
    let $lhs_i = self;
    $body
}

instead of

fn $ops_fn(self, $rhs_i: $rhs) -> Self::Output {
    let $lhs_i = self;
    $body
}

[snaar]

Arguably, you almost always want operators to be inline, so maybe you can just add inline everywhere without making it optional.

[carbotaniuman]

I'll try and figure out if I can get the macro to accept arbitrary attributes, or else I'll just mark it inline.

[carbotaniuman]

This is being addressed by #13.