The 'aria-expanded' attribute was not correctly updated on the `i` tag
when the user scrolled through the page TOC. This caused a minor issue
where an arrow (`i`) that was collapsed manually with a click would no
longer automatically expand afterward.
task-3106339
closesodoo/documentation#3236
X-original-commit: f068065d39
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>