Move reusable mouse types to iced_core

core/src/mouse/button.rs

@@ -0,0 +1,15 @@
+/// The button of a mouse.
+#[derive(Debug, Hash, PartialEq, Eq, Clone, Copy)]
+pub enum Button {
+    /// The left mouse button.
+    Left,
+
+    /// The right mouse button.
+    Right,
+
+    /// The middle (wheel) button.
+    Middle,
+
+    /// Some other button.
+    Other(u8),
+}