Improve display of release version (feature availability) data in documentation
Following on !465 (merged), let's consider and plan additional phases where we:
- Inventory/evaluate the content of existing "introduced in notes" to remove old (7.x-8.x) notes and otherwise streamline the content within them.
- Introduce an additional style and JS to hide this info by default, and offer a way of displaying it via a link or icon near the badges on applicable headers. (See previous discussion thread here.)
- Further research the needs for/uses of this info across GitLab and our customer base. Consider porting the data to features.yml for structured storage and displays that meet the needs of the relevant audiences. (See previous discussion thread here.)
Edited by Achilleas Pipinellis