Rollup merge of #103432 - jsha:box-is-not-notable, r=GuillaumeGomez

rustdoc: don't mark Box<T> as Iterator, Read, etc

Because Box<T> has pass-through implementations, rustdoc was giving it the "Notable Traits" treatment for Iterator, Read, Write, and Future, even when the type of T was unspecified.

Pin had the same problem, but just for Future.

Fixes #100320

src/test/rustdoc/doc-notable_trait_box_is_not_an_iterator.rs

@@ -0,0 +1,38 @@
+#![feature(doc_notable_trait)]
+#![feature(lang_items)]
+#![feature(no_core)]
+#![no_core]
+#[lang = "owned_box"]
+pub struct Box<T>;
+
+impl<T> Box<T> {
+    pub fn new(x: T) -> Box<T> {
+        Box
+    }
+}
+
+#[doc(notable_trait)]
+pub trait FakeIterator {}
+
+impl<I: FakeIterator> FakeIterator for Box<I> {}
+
+#[lang = "pin"]
+pub struct Pin<T>;
+
+impl<T> Pin<T> {
+    pub fn new(x: T) -> Pin<T> {
+        Pin
+    }
+}
+
+impl<I: FakeIterator> FakeIterator for Pin<I> {}
+
+// @!has doc_notable_trait_box_is_not_an_iterator/fn.foo.html '//*' 'Notable'
+pub fn foo<T>(x: T) -> Box<T> {
+    Box::new(x)
+}
+
+// @!has doc_notable_trait_box_is_not_an_iterator/fn.bar.html '//*' 'Notable'
+pub fn bar<T>(x: T) -> Pin<T> {
+    Pin::new(x)
+}