func_wrap vs macro_rules_attr vs wrapped-list

Helper crate for procedural macro authors that wish to duplicate some received function inside its body, so as to be able to wrap with some prologue, epilogue, cache-ing, etc.

Use declarative macros as proc_macro attributes. (`#[apply]` / `#[extend]` your `macro_rules!`)

Macro for wrapping elements of a list with an object, function, or another macro at compile time