Add keybind to close views

src/view.zig

@@ -126,6 +126,13 @@ pub const View = struct {
         }
     }
 
+    /// Send a close event to the view's client
+    pub fn close(self: Self) void {
+        // Note: we don't call arrange() here as it will be called
+        // automatically when the view is unmapped.
+        c.wlr_xdg_toplevel_send_close(self.wlr_xdg_surface);
+    }
+
     fn handleMap(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
         // Called when the surface is mapped, or ready to display on-screen.
         const view = @fieldParentPtr(View, "listen_map", listener.?);