When looking at latest (the default for docs.micropython.org), make it
clear that this isn't the release version.
- Changes the version in the top-left to "latest".
- Adds a message to the top of each page to explain.
For future release versions, add a short message to link to the latest
version.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
