mod: change interface for rendering of Layouts and Widgets to use a non-const pointer to the renderer instead

src/layout/VStack.zig

@@ -137,7 +137,7 @@ pub fn Layout(comptime Event: type, comptime Renderer: type) type {
             return &this.events;
         }
 
-        pub fn render(this: *@This(), renderer: Renderer) !void {
+        pub fn render(this: *@This(), renderer: *Renderer) !void {
             for (this.elements.items) |*element| {
                 switch (element.*) {
                     .layout => |*layout| {