Add a blanket From<E: IntoReport<Local>> impl for MainReport

[funsafemath]

MainReport current From impl is

impl<C: ?Sized + 'static, O: 'static, T: 'static> From<Report<C, O, T>> for MainReport {

which doesn't allow something like

fn main() -> Result<(), MainReport> {
    fs::read("file")?;
    Ok(())
}

to compile without converting the errors to reports manually or wrapping the main function

[TethysSvensson]

Thanks!