[RB] Shared variable from/to class/instance side

[Gabriel-Darbord]

I would like to have a refactoring to move a shared variable to the class or instance side, or vice versa.

Shared variables are named with a title case (first letter is uppercase), and they can be used throughout a class hierarchy.
If we want to make it a class or instance variable, we need to both move the declaration and rename the variable.

It would be equivalent to renaming the variable first, then moving the declaration.
However, the refactoring engine refuses to rename the variable with a case that is not appropriate for where the variable currently resides.