[DOCS]: Clarify GET / response on Serverless

[charlotte-hoblik]

This PR:

• clarifies the response when a user runs GET /
• updates the existing example response
• adds a new example specific to serverless deployments.

On Serverless, this endpoint will always return 8.11.0 as the version number and it is expected. Serverless offers automatic upgrades. Version is no longer something the user manages.

Based on: elastic/docs-content#1960

[github-actions]

Following you can find the validation changes against the target branch for the APIs.

No changes detected.

You can validate these APIs yourself by using the make validate target.

[charlotte-hoblik]

@leemthompo One question: I used the ::: syntax in my changes to highlight notes (screenshot attached). It renders really nicely in the built docs, but I haven’t seen anyone else use it, so I’m not sure if it’s officially supported or just working by coincidence.

Could you let me know if it’s safe to use? I’d prefer to avoid relying on something that might break later.

[leemthompo]

Thanks @charlotte-hoblik! Just suggested a rewording for clarity. On the ::: syntax, I have no idea TBH, I think @flobernd probably knows about this. 😄

I'll let @ppf and @rjernst weigh in on this too

[leemthompo]

@charlotte-hoblik you'll need to run your make generate commands again to make sure the output files are also updated

Would be nice to have screenshots of the examples too for reviewers :)

[leemthompo]

LGTM, thanks!

[github-actions]

The backport to 8.17 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-8.17 8.17
# Navigate to the new working tree
cd .worktrees/backport-8.17
# Create a new branch
git switch --create backport-4981-to-8.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 a81526b99d88f1acb13fadf64b9f1d335af72fc2
# Push it to GitHub
git push --set-upstream origin backport-4981-to-8.17
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-8.17

Then, create a pull request where the base branch is 8.17 and the compare/head branch is backport-4981-to-8.17.