This can be useful to make sure that a project builds when
its fallbacks are used on systems where external dependencies
satisfy the version requirements, or to easily hack on the sources
of a dependency for which a fallback exists.
This is a cosmetic change because github seems to interpret those
correctly. Nonetheless, it adds unnecessary noise and makes people
modifying the pages think it might be needed.
See syntax guide at https://guides.github.com/features/mastering-markdown/
This allows us to more easily have the documentation in sync with
the source code as people will have to document new features etc
right at the time where they implement it.