Rollup merge of rust-lang#113681 - aDotInTheVoid:rdj-priv-supertrait, r=GuillaumeGomez

rustdoc-json: Add test for private supertrait.

Helps with rust-lang#81359

r? ``@GuillaumeGomez``

Author: matthiaskrgr

tests/rustdoc-json/traits/private_supertrait.rs

@@ -0,0 +1,15 @@
+// ignore-tidy-linelength
+
+#![feature(no_core)]
+#![no_core]
+
+
+// @!has "$.index[*][?(@.name == 'sealed')]"
+mod sealed {
+    // @set sealed_id = "$.index[*][?(@.name=='Sealed')].id"
+    pub trait Sealed {}
+}
+
+// @count "$.index[*][?(@.name=='Trait')].inner.trait.bounds[*]" 1
+// @is    "$.index[*][?(@.name=='Trait')].inner.trait.bounds[0].trait_bound.trait.id" $sealed_id
+pub trait Trait: sealed::Sealed {}