fix(icons): Document icon requirements for notifications and activities

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/public/Activity/IEvent.php

@@ -310,6 +310,10 @@ interface IEvent {
 	public function getLink(): string;
 
 	/**
+	 * Set the absolute url for the icon (should be colored black or not have a color)
+	 *
+	 * It's automatically color inverted by clients when needed
+	 *
 	 * @param string $icon
 	 * @return $this
 	 * @throws InvalidValueException if the icon is invalid
@@ -319,6 +323,10 @@ interface IEvent {
 	public function setIcon(string $icon): self;
 
 	/**
+	 * Get the absolute url for the icon (should be colored black or not have a color)
+	 *
+	 * It's automatically color inverted by clients when needed
+	 *
 	 * @return string
 	 * @since 11.0.0
 	 */

lib/public/Notification/INotification.php

@@ -249,6 +249,10 @@ interface INotification {
 	public function getLink(): string;
 
 	/**
+	 * Set the absolute url for the icon (should be colored black or not have a color)
+	 *
+	 * It's automatically color inverted by clients when needed
+	 *
 	 * @param string $icon
 	 * @return $this
 	 * @throws InvalidValueException if the icon is invalid
@@ -258,6 +262,10 @@ interface INotification {
 	public function setIcon(string $icon): INotification;
 
 	/**
+	 * Get the absolute url for the icon (should be colored black or not have a color)
+	 *
+	 * It's automatically color inverted by clients when needed
+	 *
 	 * @return string
 	 * @since 11.0.0
 	 */