Allow deep linking to version aliases in the docs

[llucax]

What's needed?

We need to be able to use deep links to a particular version alias in the docs.

Proposed solution

Change the alias_type in the mike section in mkdocs.yml to use symlink instead of redirect.

Additional context

GitHub pages stopped supporting symlinks at some point unless they were built using GitHub Actions. Back then this was not the default and we didn't use GHA, so we had to change the config to use redirect instead. This is not ideal because we can't have deep link to a particular version that is an alias.

This setting was changed (or set explicitly to redirect) here:

• Add support and bump to mike 2.0.0 #174