[3.9] gh-105184: document that marshal functions can fail and need to be checked with PyErr_Occurred (GH-105185)#105221

ambv merged 1 commit intopython:3.9python/cpython:3.9from

miss-islington:backport-ee26ca1-3.9miss-islington/cpython:backport-ee26ca1-3.9Copy head branch name to clipboard