better document purpose of `Identifier`
@@ -105,6 +105,11 @@ impl ListSeparator {
}
}
+/// In Sass, underscores and hyphens are considered equal
+/// when inside identifiers.
+///
+/// This struct protects that invariant by normalizing all
+/// underscores into hypens.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub(crate) struct Identifier(String);
