rustdoc: "List of all items" title shown twice

[RalfJung]

As can be seen when going to https://doc.rust-lang.org/nightly/std/all.html, the "List of all items" page generated by rustdoc has a header saying "List of all items List of all items":

[jyn514]

Mentoring instructions: remove this line:

rust/src/librustdoc/html/render/mod.rs

Line 1346 in 6b56603

<span class=\"in-band\">List of all items</span>\

[jyn514]

I think this regressed in #81398. cc @bugadani, do you have time to take a look?

[bugadani]

How did that happen... Whoops, I'll fix asap

As an aside, that bug should've been "List of List of all items" for a bit of wikipedia-plagiarism.

@rustbot claim