make it clearer that Plugins have to copy the AST if they modify it.This was changed in Pharo8 as we realized that plugins might not changethe AST (as indeed the FFI plugin does not). So not doing a copy makesthings faster.
typo fix
- copy the two examples to the CoverageDemo classThis way it does not need to reference any class from the tests and isself-containedfixes #4232