Update 09.adding_animations.rst

[Xavier-IV]

Animation > Copy is outdated

Overview

The documented Animation > Copy could not be found anymore.

These are the only options when clicking Animation button:

What works instead, is with the updated suggestion with "Edit > Copy/Paste Tracks".

Simplified the documentation a bit for easier reading.

[Xavier-IV]

Edit: Updated to add image reference

[skyace65]

Superseded by #8955

[Xavier-IV]

Superseded by #8955

Awesome, thank you for the hard work!