Macro pallet_contracts::register_func

macro_rules! register_func {
    ( $reg_cb:ident, < E: $seal_ty:tt > ; ) => { ... };
    ( $reg_cb:ident, < E: $seal_ty:tt > ;
		$name:ident ( $ctx:ident $( , $names:ident : $params:ty )* )
		$( -> $returns:ty )* => $body:tt $($rest:tt)*
	) => { ... };
}