Missing docstring & restore snapshot

crates/egui/src/widget_style.rs

@@ -218,13 +218,18 @@ impl Style {
     }
 }
 
-/// The root class is present on every top-level ui
+/// The root class is a special class present on every top-level [`Ui`].
 pub const ROOT_CLASS: &str = "root";
+/// The selected class is a special class present on selected [`Button`].
 pub const SELECTED_CLASS: &str = "selected";
 
+/// A class is a static string identifier.
 pub type ClassName = Cow<'static, str>;
 
-/// The classes assigned to a widget
+/// Classes are string identifier that can be set on widget/Ui.
+///
+/// This can be used by styling engine to compute a different style
+/// based on the set of classes present on the widget/Ui.
 #[derive(Debug, Default, Clone)]
 pub struct Classes {
     classes: SmallVec<[ClassName; 5]>,

crates/egui_demo_app/tests/snapshots/clock.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:80c64fe75dfc412bb33aa977055afcb140e6bfff19128ecf5bd35318ab6773d0
-size 335380
+oid sha256:e4cff85a005ad897624f6c7a2b2ad599325ec99e0b3c9c35963f16611f283997
+size 335371

crates/egui_kittest/tests/snapshots/should_wait_for_images.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:845acb34152fb829dc24c606b1741e250f1d1fa645236ef57fce0cbda104c465
-size 2121
+oid sha256:ad75a0e568e04c20d0e3b823c7e4906c39dcd0a69a086d8e30714a9e4530d031
+size 2128

tests/egui_tests/tests/snapshots/visuals/button_image.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:31111fd16534107d74c03b798f53a013741bc1c83cf4bb24e374e4c3cac13af3
-size 11783
+oid sha256:a2a017c2b93d1920ae85792c13eafa2fd43f93b2e3bbaa5981ed3a43050c0995
+size 11808

tests/egui_tests/tests/snapshots/visuals/radio.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:5e645507bdb755dc8c30e2c3ebaa1ca1a30fb9d52395d3eb70854be8ec8203da
-size 11791
+oid sha256:4502cc58a4085d1e0f9945d0bd1d25adeefe71094ce94a210c57f113727f3a5a
+size 11806

tests/egui_tests/tests/snapshots/visuals/radio_checked.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:33fb05197d6ae6f56d79263db49fcbb9534ec5552e4712ee5dfd0c1f76dc745e
-size 12483
+oid sha256:cdedec6788b1a5026603322db9dd9f5fa398813d8aa2c56bc60acad390110501
+size 12499