[3.14] Docs: Fix a grammatical error in `Doc/c-api/arg.rst` (GH-140525)#140538

ZeroIntensity merged 1 commit intopython:3.14python/cpython:3.14from

miss-islington:backport-fc2e23c-3.14miss-islington/cpython:backport-fc2e23c-3.14Copy head branch name to clipboard