Allow creating sticky sidebar on FSE themes

[edwinho89]

What

While there are tutorials on how we can create sidebars by using Column blocks, it'd be great if there's the option to set the sidebar 'sticky' as well.

Requested from 36777854-hc

Why

Sticky sidebars allows reader to navigate, view better sidebar contents even when scrolling further downwards.

How

Some classic, older themes have the option to display sidebars, FSE themes doesn't.

[Greatdane]

📌 FINDINGS/SCREENSHOTS/VIDEO

• I guess the 'sticky' request could be argued for many blocks, such as the header as well.

📌 ACTIONS

• Feature request kept

[katiebethbrown]

@edwinho89 and @Greatdane - Gutenberg 15.0 adds the ability to make group blocks sticky, which sounds very similar to this request. 👍

https://make.wordpress.org/core/2023/01/20/whats-new-in-gutenberg-15-0-18-january/#sticky-position