message: fix snippet in 'functions' page
diff: @@ -50,10 +50,10 @@ same time it can be harder to reason on what your program will do.
  Rune functions can be easily set up and called from Rust.
  ```rust,noplaypen
  -{{#include ../../examples/examples/basic_add.rs}}
  +{{#include ../../examples/examples/minimal.rs}}
  ```
  ```text
  -$> cargo run --example basic_add
  +$> cargo run --example minimal
  output: 43
  ```
  