[chore]: update order of db systems on readme

[maryliag]

Changes

Small change to alphabetical order of db system, to improve readability.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[joaopgrassi]

@maryliag did you do these changes manually? AFAIK the order in the yaml shouldn't matter, but the tooling when generating the markdown should order alphabetically already.

Do you happen to know? CC @jsuereth @lquerel as the weaver experts

[maryliag]

The order in the yaml file is kept in the final readme. So changing the yaml file and regenerating with make table-generation attribute-registry-generation was responsible for updating the tables on the files.

The file docs/attributes-registry/db.md was the only one that got the examples updated with the command, but not the table itself, so that one I did manually.

the tooling when generating the markdown should order alphabetically already.

that is not what is happening, it's just keeping the order of the yaml