Add deinit to TreeWidget

src/main.zig

@@ -34,6 +34,8 @@ const Ui = struct {
     }
 
     pub fn deinit(self: *Ui) void {
+        self.treeWidget.deinit();
+
         self.uiFont.deinit();
         self.codeFont.deinit();
         ttf.quit();
@@ -70,6 +72,8 @@ const TreeWidget = struct {
         return .{};
     }
 
+    pub fn deinit(self: TreeWidget) void {}
+
     pub fn render(self: TreeWidget, ui: Ui) !void {
         var surface = try ui.uiFont.renderBlended("Hello world", .{ .r = 255, .g = 255, .b = 255 });
         defer surface.deinit();