[docs] [issue30621] import json before using json module in tutorial Input and Output

[Masaki Suketa]

New submission from Masaki Suketa:

In Input and Output tutorial, use json module without `import json`.

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assignee: docs at python
components: Documentation
messages: 295626
nosy: docs at python, suketa
priority: normal
pull_requests: 2139
severity: normal
status: open
title: import json before using json module in tutorial Input and Output
type: resource usage
versions: Python 3.6

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30621>
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