Derive Macro Patch 

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

Derive macro that generates the Patch trait implementation.

The generated patch method:

• assigns fields directly by default,
• recursively calls patch on fields marked with #[patchable],
• respects #[patchable(skip)] by omitting those fields from patching.