Use f-strings in asyncio-task code examples (GH-10035)


Replace str.format with f-strings in the code examples of asyncio-task documentation.
(cherry picked from commit 9f43fbbd9dfc78125c9533ce1dfe33ff5d15aa45)

Co-authored-by: Mariatta <Mariatta@users.noreply.github.com>
1 file changed