guide: add String example usage to supported types

guide/src/reference/types.md

@@ -73,6 +73,18 @@ Copies the string's contents back and forth between the JavaScript
 garbage-collected heap and the Wasm linear memory with `TextDecoder` and
 `TextEncoder`
 
+### Example Rust Usage
+
+```rust
+{{#include ../../../examples/guide-supported-types-examples/src/string.rs}}
+```
+
+### Example JavaScript Usage
+
+```js
+{{#include ../../../examples/guide-supported-types-examples/string.js}}
+```
+
 ## `char`
 
 | `T` parameter | `&T` parameter | `&mut T` parameter | `T` return value | `Option<T>` parameter | `Option<T>` return value | JavaScript representation |