rustdoc: show attributes on enum variants

mostly for #[non_exhaustive]

Author: lolbinarycat

src/librustdoc/html/render/print_item.rs

@@ -1702,6 +1702,7 @@ fn render_enum_fields(
                 if v.is_stripped() {
                     continue;
                 }
+                write!(w, "{}", render_attributes_in_pre(v, TAB, cx))?;
                 w.write_str(TAB)?;
                 match v.kind {
                     clean::VariantItem(ref var) => match var.kind {

tests/rustdoc/enum/enum-variant-non_exhaustive.rs

@@ -0,0 +1,9 @@
+#![crate_name = "foo"]
+
+//@ snapshot type-code 'foo/enum.Type.html' '//pre[@class="rust item-decl"]/code'
+pub enum Type {
+    #[non_exhaustive]
+    // attribute that should not be shown
+    #[warn(unsafe_code)]
+    Variant,
+}

tests/rustdoc/enum/enum-variant-non_exhaustive.type-code.html

@@ -0,0 +1,4 @@
+<code>pub enum Type {
+    #[non_exhaustive]
+    Variant,
+}</code>