Plays a code tour committed to a branch. The editor opens each file, scrolls to
the lines being discussed, dims everything else, and reads the explanation out
loud while you look at the code.
A tour is a .docent/tour.json file in the repo root, so it travels with the
branch: anyone who checks out the branch plays the same walkthrough.
Docent: open the tour to start, or the status bar item
ctrl+alt+space play or pause, ctrl+alt+[] step, ctrl+alt+v voice
Every field in the panel is editable and saves back to tour.json