Change enum.item.number to Smart instead of Option (#6609)

crates/typst-eval/src/markup.rs

@@ -251,7 +251,7 @@ impl Eval for ast::EnumItem<'_> {
         let body = self.body().eval(vm)?;
         let mut elem = EnumItem::new(body);
         if let Some(number) = self.number() {
-            elem.number.set(Some(number));
+            elem.number.set(Smart::Custom(number));
         }
         Ok(elem.pack())
     }

crates/typst-html/src/rules.rs

@@ -103,7 +103,7 @@ const ENUM_RULE: ShowFn<EnumElem> = |elem, _, styles| {
 
     let body = Content::sequence(elem.children.iter().map(|item| {
         let mut li = HtmlElem::new(tag::li);
-        if let Some(nr) = item.number.get(styles) {
+        if let Smart::Custom(nr) = item.number.get(styles) {
             li = li.with_attr(attr::value, eco_format!("{nr}"));
         }
         // Text in wide enums shall always turn into paragraphs.

crates/typst-library/src/model/enum.rs

@@ -220,7 +220,7 @@ impl EnumElem {
 pub struct EnumItem {
     /// The item's number.
     #[positional]
-    pub number: Option<u64>,
+    pub number: Smart<u64>,
 
     /// The item's body.
     #[required]

tests/suite/model/enum.typ

@@ -56,6 +56,10 @@ a + 0.
    enum.item(5)[Fifth]
 )
 
+--- enum-item-number-optional ---
+#enum.item[First]
+#enum.item[Second]
+
 --- enum-numbering-pattern ---
 // Test numbering pattern.
 #set enum(numbering: "(1.a.*)")
@@ -217,7 +221,7 @@ a + 0.
 
 --- issue-2530-enum-item-panic ---
 // Enum item (pre-emptive)
-#enum.item(none)[Hello]
+#enum.item(auto)[Hello]
 #enum.item(17)[Hello]
 
 --- issue-5503-enum-in-align ---