build-bundle: Document --from-commit
build-bundle: Document --from-commit

This option was missing from the docs.

Closes: #2528
Approved by: mwleeds

flatpak/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak