mod: replace Layout.content with Layout.render

The App.Renderer is used for the new `Layout.render` method. Each layout
renders itself now with corresponding renderers which might only update
parts of the screen, etc.

src/main.zig

@@ -24,7 +24,9 @@ pub fn main() !void {
     const allocator = gpa.allocator();
 
     var app: App = .{};
-    var renderer: App.Renderer = .{};
+    const renderer: App.Renderer = .{};
+    // FIX: when not running fullscreen, the application needs to screen down accordingly to display the contents
+    // -> size hint how much should it use?
 
     const mainFile = try std.fs.cwd().openFile("./src/main.zig", .{});
     var mainFileText = App.Widget.RawText.init(allocator, mainFile);
@@ -35,17 +37,11 @@ pub fn main() !void {
     appFile.close();
 
     var spacer = App.Widget.Spacer.init();
-    var framing = App.Layout.Framing.init(allocator, .{
-        .widget = App.Widget.createFrom(&mainFileText),
-    });
-    var hstack = App.Layout.HStack.init(allocator, .{
-        App.Layout.createFrom(&framing),
-    });
     // TODO: corresponding contents need to be filled out by the layout accordingly!
     var vstack = App.Layout.VStack.init(allocator, .{
         App.Widget.createFrom(&appFileText),
-        App.Layout.createFrom(&hstack),
         App.Widget.createFrom(&spacer),
+        App.Widget.createFrom(&mainFileText),
     });
     var layout = App.Layout.createFrom(&vstack);
     defer layout.deinit();
@@ -88,6 +84,6 @@ pub fn main() !void {
         for (events.items) |e| {
             app.postEvent(e);
         }
-        try renderer.render(try layout.content());
+        try layout.render(renderer);
     }
 }