Problem: Sometimes automatic lockfile synchronization after `:restart`
might fail, like due to bad/absent Internet connection. This would
remove failed to install entries from the lockfile (since they are not
on disk and lockfile is meant to lock the latest plugin version on
disk).
Solution: Document that this should be treated as an unwanted update and
use steps similar to "Revert plugin after an update" use case.
42e9d8dfd1
