[DOCS] Add examples for delete by query API

[lcawl]

Relates to #2482

This PR adds examples copied from https://www.elastic.co/guide/en/elasticsearch/reference/master/docs-delete-by-query.html. It also edits the descriptions and adds missing @doc_id details.

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
delete_by_query_rethrottle	🟢	1/1	1/1
delete_by_query	🟢	5/5	4/4
tasks.get	🟢	10/10	10/10

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

[szabosteve]

LGTM

[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-3574-to-8.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 083284a72e4c62753fadcf83a69dbc0504e3a7e4
# Push it to GitHub
git push --set-upstream origin backport-3574-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-3574-to-8.17.

[lcawl]

💚 All backports created successfully

Status	Branch	Result
✅	8.x

Questions ?

Please refer to the Backport tool documentation

[lcawl]

💚 All backports created successfully

Status	Branch	Result
✅	8.17

Questions ?

Please refer to the Backport tool documentation