There is little visible difference from the previous version, except

• Change right sidebar title from "Contents" to "On this page"

I expected style updates to make

headings look more separated from

elements, but no such updates.

Instead, we may put a thin rule below, for example, "Mathematics", but this is a work for another ticket.

Depends on #34434

CC: @mkoeppe

Component: packages: standard

Author: Kwankyu Lee

Branch/Commit: 107b88e

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34656