(fix) Workaround for duplicate decorators in def -> async def

[MementoRC]

Related to: #55
Observation:
- When Asyncifing a decorated function, the decorators are duplicated
Understanding:
- In apply() method of_ReplaceCodeSegmentAction, the lines exclude the decorators (from position_for())
- Building the replacement is based on the context, which includes the decorators
- Replacing the lines slice with the replacement ends up duplicating the decorators
Proposal:
- A possible solution is to include the decorators in the lines since _resyntesize() works with the
context that includes the decorators