Add Default and Hash to icu::list::ListLength (#4507)

Same as #4503 and #4506 for icu::list

components/list/src/lib.rs

@@ -106,7 +106,7 @@ pub use ListError as Error;
 /// Represents the style of a list. See the
 /// [CLDR spec](https://unicode.org/reports/tr35/tr35-general.html#ListPatterns)
 /// for an explanation of the different styles.
-#[derive(Copy, Clone, PartialEq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
 #[non_exhaustive]
 pub enum ListLength {
     /// A typical list
@@ -118,3 +118,9 @@ pub enum ListLength {
     // *Important*: When adding a variant here, make sure the code in
     // ListFormatterPatterns::{start, middle, end, pair} stays panic-free!
 }
+
+impl Default for ListLength {
+    fn default() -> Self {
+        Self::Wide
+    }
+}