Move cooldown example instruction text according to example visual guidelines (#19381)

# Objective

Use the same text positioning as other examples that have instruction
text.

See
https://bevyengine.org/learn/contribute/helping-out/creating-examples/#visual-guidelines

examples/usage/cooldown.rs

@@ -68,8 +68,8 @@ fn setup(
         Text::new("*Click some food to eat it*"),
         Node {
             position_type: PositionType::Absolute,
-            top: Val::Px(5.0),
+            top: Val::Px(12.0),
-            left: Val::Px(15.0),
+            left: Val::Px(12.0),
             ..default()
         },
     ));