sd_hide_title, short and long title

[paugier]

I'm working on a new documentation website for Mercurial, which can currently be viewed at

https://mercurial.pages.heptapod.net/hg-website/topic/default/with-sphinx

I have an issue with this page https://mercurial.pages.heptapod.net/hg-website/topic/default/with-sphinx/about.html

I'd like it to appear as "About" in the left panel and with a long title "Mercurial source control management".

I used

---
sd_hide_title: true
---

# About

# Mercurial source control management

which works but I get two titles "About" and "Mercurial source control management" in the right TOC ("On this page").

I like to learn how I could get

• short title "About" on the left TOC
• long title on the middle
• clean right TOC without "About" and "Mercurial source control management"