docs/mdbook: drop pagetoc

It is currently not working.

TODO: investigate and fix

docs/mdbook/book.toml

@@ -7,8 +7,7 @@ title = "nixvim docs"
 
 [output.html]
 site-url = "@SITE_URL@"
-additional-js = ["theme/pagetoc.js"]
-additional-css = ["custom.css", "theme/pagetoc.css"]
+additional-css = ["custom.css"]
 git-repository-url = "https://github.com/nix-community/nixvim"
 
 # Redirect targets must be relative to their origin;
@@ -21,5 +20,3 @@ enable = true
 level = 0
 
 [preprocessor.alerts]
-
-[preprocessor.pagetoc]

docs/mdbook/default.nix

@@ -331,7 +331,6 @@ pkgs.stdenv.mkDerivation (finalAttrs: {
   buildInputs = [
     pkgs.mdbook
     pkgs.mdbook-alerts
-    pkgs.mdbook-pagetoc
   ];
 
   # Build a source from the fileset containing the following paths,