Derive Macro Patchable 

#[derive(Patchable)]
{
    // Attributes available to this derive:
    #[patchable]
}

Derive macro that generates the companion Patch type and Patchable impl.

The generated patch type:

• mirrors the original struct shape (named/tuple/unit),
• includes fields unless marked with #[patchable(skip)],
• implements Clone and PartialEq,
• also derives serde::Deserialize when the serde feature is enabled for the macro crate.

The Patchable impl sets type Patch = <StructName>Patch<...> and adds any required generic bounds.

When the impl_from feature is enabled for the macro crate, a From<Struct> implementation is also generated for the patch type.