- remove pruneFilters.Contains for checks, as this is already
handled by pruneFilters.ExactMatch.
- Update GoDoc to better describe the function's functionality
- Use a swtich instead of if/else.
This function should be moved to a separate package; possibly splitting
it out to a "Merge" function that accepts two filter.Args as argument.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>