Give the text example's aligned labels the width to align in

All three sat in the middle of a box the width of the widest of them, so
left, centred and right were the same picture. `text_align` puts the glyphs
somewhere in the box the text is given, and a text that reports the width of
its own glyphs is given exactly that -- there is nowhere for it to sit.
Declaring `rel(1.0)` on each hands it the row instead. (Bryan, 2026-09-17.)

examples/text.rs

@@ -28,10 +28,14 @@ impl DefaultAppState for State {
             .pad(16)
             .background(panel());
 
+        // Each one takes the whole width, because `text_align` puts the
+        // glyphs somewhere in the box the text is given and a text that
+        // reports the width of its own glyphs is given exactly that.
+        let label = |text: &str, align| wtext(text).size(24).text_align(align).width(rel(1.0));
         let aligned = (
-            wtext("left").size(24).text_align(Align::LEFT),
+            label("left", Align::LEFT),
-            wtext("centred").size(24).text_align(Align::CENTER),
+            label("centred", Align::H_CENTER),
-            wtext("right").size(24).text_align(Align::RIGHT),
+            label("right", Align::RIGHT),
         )
             .span(Dir::DOWN)
             .gap(8)