update two rustdoc comments

src/librustdoc/clean/utils.rs

@@ -397,10 +397,10 @@ crate fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
             | Union | Mod | ForeignTy | Const | Static | Macro(..) | TraitAlias),
             i,
         ) => (i, kind.into()),
-        // This is part of a trait definition; document the trait.
+        // This is part of a trait definition or trait impl; document the trait.
         Res::SelfTy { trait_: Some(trait_def_id), alias_to: _ } => (trait_def_id, ItemType::Trait),
-        // This is an inherent impl; it doesn't have its own page.
-        Res::SelfTy { trait_: None, alias_to: Some((impl_def_id, _)) } => return impl_def_id,
+        // This is an inherent impl or a type definition; it doesn't have its own page.
+        Res::SelfTy { trait_: None, alias_to: Some((item_def_id, _)) } => return item_def_id,
         Res::SelfTy { trait_: None, alias_to: None }
         | Res::PrimTy(_)
         | Res::ToolMod