Merge pull request #4551 from RosettaCommons/vmullig/fix_clang_tidy_citationmanager
Fixing clang tidy test. I forgot to switch "virtual" to "override" in a recent merge.
This also updates the code templates for general classes to use `override` instead of `virtual` for the destructor. (`ReferenceCount::~ReferenceCount()` is `virtual`.)