docs: consolidate ReJSON documentation into single section}
- Merge duplicate "Redis 8 ReJSON Support" section into the main
"Redis 8 Module Support" heading, removing redundant content
- Rename section to "Redis 8 Module Support (ReJSON)" for clarity
- Add format and copy actions to the ReJSON feature description
- Add JSON key tree icon and Add Key dialog details as a new bullet
- Remove standalone ReJSON section to eliminate duplication