📘 Document where certain menus and buttons are found in FL Studio

Just found out Sphinx's [:menuselection:](https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-menuselection) role.

FL Studio changed the positioning of certain things like `Sampler` a lot, These locations are with respect to FL Studio 20.8.4.
Super old versions of FL will definitely have different label names and certain things missing / placed elsewhere.