[issue32262] Fix linting errors in asyncio code; use f-strings consistently

[Serhiy Storchaka]

New submission from Serhiy Storchaka <storchaka+cpython at gmail.com>:

Usually we don't do such kind of changes. This spoils the output of `git annotate` and `git blame` and makes harder researching the history.

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nosy: +pitrou, rhettinger, serhiy.storchaka

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32262>
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