[docs] [issue34161] (good first issue) Tutorial 7.1 str.format() code example syntax error

[miss-islington]

Change by miss-islington <mariatta.wijaya+miss-islington at gmail.com>:


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pull_requests: +11308, 11309

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue34161>
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