message: fix snippet in 'closures' page
diff: @@ -55,15 +55,12 @@ pointers out of the virtual machine using the `Function` type.
  This allows you to write code that takes a function constructed in Rune, and use
  it for something else.
  -Below we showcase this, with the help of the `rune_s!` macro from the `testing`
  -module.
  -
  ```rust,noplaypen
  -{{#include ../../examples/examples/call_rune_fn.rs}}
  +{{#include ../../examples/examples/rune_function.rs}}
  ```
  ```text
  -$> cargo run --example call_rune_fn
  +$> cargo run --example rune_function
  4
  8
  ```
  