support extern crate

[gilescope]

I'm looking at paritytech/polkadot-sdk#2101 but in your_first_pallet I can't see how to add in the alloc statement at the start of the crate. I thought this might work:

#[docify::export]
extern crate alloc;

but seems not. Any thoughts?

[sam0x17]

this line essentially governs what items are supported: https://github.com/sam0x17/docify/blob/main/macros/src/lib.rs#L618

So if all of those traits are implemented for ItemExternCrate then it should be supported. If not, would be pretty easy to add support by submitting a PR that impls whatever traits are missing on that item. I don't have much bandwidth for this right now but happy to accept a PR that adds this

[sam0x17]

what's weird is it looks like extern crate should be supported: https://github.com/sam0x17/docify/blob/main/macros/src/lib.rs#L173

[sam0x17]

actually I would try giving it an explicit name like #[docify::export(some_name)], might be a naming collision