Issue Description:

Referencing instance member was thoroughly discussed in SE-009. There are different opinions on this topic and I think we could make a refactoring that will help convert from one style to the other. This will surely help teams to enforce guidelines and make transitions easier. This consists of two refactors:

• removing unnecessary `self` keywords if the reference to the instance member is unambiguous ( we don't have the same symbol in local scope)

• adding `self` references in all of the places that are referencing instance members

The most useful would be to have it able to touch multiple files at once, but since it's not available we could limit to the range selected by the user.