[3.12] gh-108669: unittest: Fix documentation for TestResult.collectedDurations (GH-108670)#108672

Yhg1s merged 1 commit intopython:3.12python/cpython:3.12from

miss-islington:backport-6c484c3-3.12miss-islington/cpython:backport-6c484c3-3.12Copy head branch name to clipboard