Make the Collect trait part of the public api

[konstin]

It's currently not possible to write a function generic over Twhere T is an inventory.

To rewrite the example given in the docs page:

fn print_inventory<T: inventory::Collect>() {
    for flag in inventory::iter::<T> {
        println!("-{}, --{}", flag.short, flag.name);
    }
}

This does already work, but the Collect trait is currently #[doc(hidden)]. My specific use case is doing the following, combined with two proc macros and a helper traits:

/// Allows arbitrary pymethod blocks to submit their methods, which are eventually collected by pyclass
pub trait PyMethodsInventory: inventory::Collect {
    /// Create a new instance
    fn new(methods: &'static [PyMethodDefType]) -> Self;

    /// Returns the methods for a single impl block
    fn get_methods(&self) -> &'static [PyMethodDefType];
}

[dtolnay]

Fixed in 0.1.3.

[konstin]

Thank you!