remove code for recursive Deref in sidebar

fix #85037

src/test/rustdoc/issue-85037.rs

@@ -0,0 +1,22 @@
+use std::ops::Deref;
+
+pub struct A {}
+impl A { pub fn foo_a(&self) {} }
+
+pub struct B {}
+impl B { pub fn foo_b(&self) {} }
+
+pub struct C {}
+impl C { pub fn foo_c(&self) {} }
+
+// @has issue_85037/struct.A.html '//div[@class="sidebar-links"]' 'foo_b'
+impl Deref for A {
+    type Target = B;
+    fn deref(&self) -> &B { todo!() }
+}
+
+// @!has issue_85037/struct.A.html '//div[@class="sidebar-links"]' 'foo_c'
+impl Deref for B {
+    type Target = C;
+    fn deref(&self) -> &C { todo!() }
+}