Placing version identifers in the docs

The docs as published don't contain any version switchers or even any identifiers for which version the docs you are consuming apply to. I don't know how to access the guide for past versions.

For example:

Python::attach is available in 0.26-dev.
Python::attach is not available in stable 0.25

The user guide for stable pyo3 points to https://pyo3.rs/ which redirects to https://pyo3.rs/main, which seems to be the dev branch, so the guide for stable is not actually the guide for stable.

And it includes lots examples that don't seem to work:

use pyo3::prelude::*;

fn main() -> PyResult<()> {
    Python::attach(|py| {
        let builtins = PyModule::import(py, "builtins")?;
        let total: i32 = builtins
            .getattr("sum")?
            .call1((vec![1, 2, 3],))?
            .extract()?;
        assert_eq!(total, 6);
        Ok(())
    })
}

error[E0599]: no function or associated item named `attach` found for struct `pyo3::Python` in the current scope                                                                                                                                          
   --> rust\main.rs:19:13
    |
19  |     Python::attach(|py| {
    |             ^^^^^^ function or associated item not found in `Python<'_>`

Start by comparing the stable documentation link at https://pyo3.rs/ with https://pyo3.rs/main and checking where the published guide identifies its version. Verify the documented Python::attach example against stable 0.25; done means stable and development docs are distinguishable and examples match the version they document.