Bring UI crate up to date

crates/ui/src/tokens.rs

@@ -0,0 +1,18 @@
+use gpui2::geometry::AbsoluteLength;
+
+#[derive(Clone, Copy)]
+pub struct Token {
+    pub list_indent_depth: AbsoluteLength,
+}
+
+impl Default for Token {
+    fn default() -> Self {
+        Self {
+            list_indent_depth: AbsoluteLength::Rems(0.5),
+        }
+    }
+}
+
+pub fn token() -> Token {
+    Token::default()
+}