guide: Add bool example to supported types section

examples/guide-supported-types-examples/bool.js

@@ -0,0 +1,9 @@
+import {
+  take_char_by_value,
+  return_char,
+} from './guide_supported_types_examples';
+
+take_bool_by_value(true);
+
+let b = return_bool();
+console.log(typeof b); // "boolean"

examples/guide-supported-types-examples/src/bool.rs

@@ -0,0 +1,9 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn take_bool_by_value(x: bool) {}
+
+#[wasm_bindgen]
+pub fn return_bool() -> bool {
+    true
+}

examples/guide-supported-types-examples/src/lib.rs

@@ -8,3 +8,4 @@ pub mod exported_types;
 pub mod str;
 pub mod string;
 pub mod char;
+pub mod bool;