Rollup merge of #61263 - GuillaumeGomez:valid-html, r=Manishearth

Don't generate div inside header (h4/h3/h...) elements

Fixes #60865.

According to the HTML spec, we're not supposed to put `div` elements inside heading elements (h4/h3/h...). It doesn't change the display as far as I could tell.

r? @QuietMisdreavus

src/librustdoc/html/render.rs

@@ -3804,7 +3804,7 @@ fn render_attributes(w: &mut dyn fmt::Write, it: &clean::Item, top: bool) -> fmt
         }
     }
     if attrs.len() > 0 {
-        write!(w, "<div class=\"docblock attributes{}\">{}</div>",
+        write!(w, "<span class=\"docblock attributes{}\">{}</span>",
                if top { " top-attr" } else { "" }, &attrs)?;
     }
     Ok(())