The Actions VM image containing v2.7.6 of the CodeQL CLI has now fully
rolled out, so we no longer need to download the latest CodeQL bundle to
use this CLI and include this repo in the ML-powered queries beta.
This commit switches to the bleeding edge, main branch of the
codeql action. This helps us test the action before merging all
of the new changes into main, which occurs roughly once a week.
If there are commits that introduce bugs in codeql-action, then
we will be more likely to catch it before releasing to the world
if we are using it in this extension.
This query ensures that all of our files marked as "pure" remain that
way. In this case "pure" means that it does not depend on vscode and
can therefore be run in tests outside of a runtime environment.
This commit also explicitly moves all of our "pure" files to the
`src/pure` directory.
