Updated documentation for adjust_brightness function

crate/src/effects.rs

@@ -547,15 +547,17 @@ pub fn solarize_retimg(photon_image: &PhotonImage) -> PhotonImage {
 ///
 /// # Arguments
 /// * `img` - A PhotonImage that contains a view into the image.
-/// * `brightness` - A u8 to add/subtract to the brightness.
+/// * `brightness` - A u8 to add or subtract to the brightness. To increase
+/// the brightness, pass a positive number (up to 255). To decrease the brightness,
+/// pass a negative number instead.
 /// # Example
 ///
 /// ```no_run
 /// use photon_rs::effects::adjust_brightness;
 /// use photon_rs::native::open_image;
 ///
 /// let mut img = open_image("img.jpg").expect("File should open");
-/// adjust_brightness(&mut img, 10_u8);
+/// adjust_brightness(&mut img, 10_i16);
 /// ```
 #[cfg_attr(feature = "enable_wasm", wasm_bindgen)]
 pub fn adjust_brightness(photon_image: &mut PhotonImage, brightness: i16) {