Rustdoc accessibility: use real headers for doc items

Part of #87059

Partially reverts #84703

Preview at: https://notriddle.com/notriddle-rustdoc-test/real-headers/std/index.html

1 files changed, 5 insertions, 0 deletions

diff --git a/src/tools/html-checker/main.rs b/src/tools/html-checker/main.rs
index bf2830254e8..7bdf527d884 100644
--- a/src/tools/html-checker/main.rs
+++ b/src/tools/html-checker/main.rs
@@ -15,6 +15,11 @@ fn check_html_file(file: &Path) -> usize {
         "MISSING_ENDTAG_BEFORE",
         "INSERTING_TAG",
         "DISCARDING_UNEXPECTED",
+        // This error is caused by nesting the Notable Traits tooltip within an <h4> tag.
+        // The solution is to avoid doing that, but we need to have the <h4> tags for accessibility
+        // reasons, and we need the Notable Traits tooltip to help everyone understand the Iterator
+        // combinators
+        "TAG_NOT_ALLOWED_IN",
     ];
     let to_mute_s = to_mute.join(",");
     let mut command = Command::new("tidy");