cleanup of obsolete comments and dead code

This removes the App.Renderer.Buffered, which was not improving on the
direct renderer, which has a simpler implementation and was keept for
this regard.

src/layout/Margin.zig

@@ -9,7 +9,7 @@ const isTaggedUnion = @import("../event.zig").isTaggedUnion;
 const Error = @import("../event.zig").Error;
 const Key = terminal.Key;
 
-const log = std.log.scoped(.layout_marging);
+const log = std.log.scoped(.layout_margin);
 
 pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: type) type {
     if (!isTaggedUnion(Event)) {
@@ -32,7 +32,6 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
         events: Events = undefined,
         config: Config = undefined,
 
-        // TODO: marging (for all 4 directions - relative!)
         const Config = struct {
             margin: ?u8 = undefined,
             left: u8 = 0,