fix(widget): respect size for RawText and Spacer Widgets

src/widget/Spacer.zig

@@ -11,6 +11,8 @@ pub fn Widget(comptime Event: type, comptime Renderer: type) type {
         @compileError("Provided user event `Event` for `Layout(comptime Event: type)` is not of type `union(enum)`.");
     }
     return struct {
+        size: terminal.Size = undefined,
+
         pub fn init() @This() {
             return .{};
         }
@@ -20,15 +22,17 @@ pub fn Widget(comptime Event: type, comptime Renderer: type) type {
         }
 
         pub fn handle(this: *@This(), event: Event) ?Event {
-            _ = this;
-            _ = event;
+            switch (event) {
+                .resize => |size| {
+                    this.size = size;
+                },
+                else => {},
+            }
             return null;
         }
 
         pub fn render(this: *@This(), renderer: Renderer) !void {
-            // FIX: this should rather clear the `terminal.Size` provided through the event system using the _renderer_.
-            _ = this;
-            _ = renderer;
+            try renderer.clear(this.size);
         }
     };
 }