Rename the symbol at point.

def refactor_rename_at_point(self, offset, new_name, in_hierarchy, docs):
        """Rename the symbol at point."""
        try:
            refactor = Rename(self.project, self.resource, offset)
        except RefactoringError as e:
            raise Fault(str(e), code=400)
        return self._get_changes(refactor, new_name,
                                 in_hierarchy=in_hierarchy, docs=docs)