FormatDestination returns the namespace/name format for the destination.
This is different from (*api.Intention).DestinationString in that the
default namespace is not omitted.
FormatSource returns the namespace/name format for the source. This is
different from (*api.Intention).SourceString in that the default namespace
is not omitted.
ParseIntentionTarget parses a target of the form <namespace>/<name> and returns
the two distinct parts. In some cases the namespace may be elided and this function
will return the empty string for the namespace then.