Question: who does the voice of dipper in gravity falls
[{'answer': 'Jason Morgan Ritter'}, {'provenance': [{'wikipedia_id': '331052', 'title': 'Jason Ritter', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 433, 'bleu_score': 0.777008879557174, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18427349102842388780}, 'section': 'Section::::Abstract.'}]}]