Major Description
The UNMARK action in Ruta should only remove the matched annotation by default. The problem is that two annotations with the same offset and type cannot be reduced to only one. Example:
T{CONTAINS(T,2,100) -> UNMARK(T)};
This rule removes all T annotations with the same offset with the first apply of the rule.
If the matched annotation (e.g., something greedy was applied) is not of the type given by the argument, then use the current strategy with the begin acnhors.