More Powerful Closure Captures

This crate provides simple macros letting you express more powerful closure captures. For example, you can capture the clone of a value:

```rust use std::rc::Rc;

let myval = Rc::new(1); captures::capture!(clone myval, move || { // my_val is cloned here! }); ```

You can also capture arbitrary expressions and override the Edition-2021 capture semantics. Best of all, you can even specify that your closure should not capture any variables outside the ones you've listed:

rust let a = 1; let b = 2; captures::capture_only!(clone a, move || { a + b // errors: `b` is unknown })

Consult the full documentation for the details.