Hello everyone,
With RawTherapee there is an experimental “branch” to remove the spots (spot-removal-tool by Hombre57).
It has been in the working for years now.
Its developer has not find the time yet to finalize it and release it (so, do not hold your breath to get it…).
Btw, with Darktable, an open source software, you have this feature (clone tool) if you really need it right now…
Needless to say, with every commercial RAW software you can also get this option as well.