Remove pagetoc

This has been subsumed by the update to mdbook 0.5. I just forgot
to remove this in rust-lang/rustc-dev-guide#2652.

Author: ehuss

src/doc/rustc-dev-guide/README.md

@@ -65,11 +65,6 @@ following example.
 ENABLE_LINKCHECK=1 mdbook serve
 ```
 
-### Table of Contents
-
-Each page has a TOC that is automatically generated by `pagetoc.js`.
-There is an associated `pagetoc.css`, for styling.
-
 ## Synchronizing josh subtree with rustc
 
 This repository is linked to `rust-lang/rust` as a [josh](https://josh-project.github.io/josh/intro.html) subtree. You can use the [rustc-josh-sync](https://github.com/rust-lang/josh-sync) tool to perform synchronization.

src/doc/rustc-dev-guide/book.toml

@@ -15,9 +15,7 @@ edit-url-template = "https://github.com/rust-lang/rustc-dev-guide/edit/main/{pat
 additional-js = [
   "mermaid.min.js",
   "mermaid-init.js",
-  "pagetoc.js",
 ]
-additional-css = ["pagetoc.css"]
 
 [output.html.search]
 use-boolean-and = true