Missing documentation in old versions after removing docs from the stable version

### What do you see as an issue?

After removing documentation from the stable version it is removed from old versions also and links in old version end up being broken. Current relevant example:

- [deprecated code from providers](#44559) have been removed. Documenation have been removed from the stable version.
- documentation in old version (it is still relevant there) has been removed, e.g. [MsSqlOperator](https://airflow.apache.org/docs/apache-airflow-providers-microsoft-mssql/stable/_api/airflow/providers/microsoft/mssql/operators/mssql/index.html#airflow.providers.microsoft.mssql.operators.mssql.MsSqlOperator)
- links leading to pages in old versions also broken, see links to operators (`MySqlOperator`, `PostgresOperator`, `MsSqlOperator` etc.) in [operators](https://airflow.apache.org/docs/apache-airflow/2.9.0/core-concepts/operators.html)

### Solving the problem

Documentation removed in the stable version should not be removed from old versions.

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

Start by comparing the stable and 2.9.0 documentation for MsSqlOperator and the operators page, including the links to MySqlOperator and PostgresOperator. Trace how documentation is retained across versions; done means documentation still relevant to an old version and its links remain available after removal from stable.

Written by the indexing model from the issue text.