added missing asciidoc&rdoc support to the wiki editor

What does this MR do?

With !8036 fixes issues addressed in #24041 (moved) & #24042 (moved) .

Are there points in the code the reviewer needs to double check?

I tried to maintain the code changes without much affecting the existing behavior and code base. JS Style needs to be confirmed. New file mode needs to be checked.

Why was this MR needed?

Issue/bug resolution

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #24041 (moved), #24042 (moved)