make item_keyword return impl fmt::Display

Author: yotamofek

src/librustdoc/html/render/print_item.rs

@@ -265,7 +265,7 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut String)
             format_args!("{}", item_constant(cx, item, &ci.generics, &ci.type_, &ci.kind)),
         ),
         clean::ForeignTypeItem => write_str(buf, format_args!("{}", item_foreign_type(cx, item))),
-        clean::KeywordItem => item_keyword(buf, cx, item),
+        clean::KeywordItem => write_str(buf, format_args!("{}", item_keyword(cx, item))),
         clean::TraitAliasItem(ref ta) => item_trait_alias(buf, cx, item, ta),
         _ => {
             // We don't generate pages for any other type.
@@ -2142,8 +2142,11 @@ fn item_foreign_type<'a, 'tcx>(
     })
 }
 
-fn item_keyword(w: &mut String, cx: &Context<'_>, it: &clean::Item) {
-    write_str(w, format_args!("{}", document(cx, it, None, HeadingOffset::H2)));
+fn item_keyword<'a, 'tcx>(
+    cx: &'a Context<'tcx>,
+    it: &'a clean::Item,
+) -> impl fmt::Display + 'a + Captures<'tcx> {
+    document(cx, it, None, HeadingOffset::H2)
 }
 
 /// Compare two strings treating multi-digit numbers as single units (i.e. natural sort order).