gh-152052: Fix misleading json error for \uXXXX escape at end of input#152053

StanFromIreland merged 3 commits into

python:mainpython/cpython:mainfrom

tonghuaroot:fix-json-uXXXX-eof-unterminatedtonghuaroot/cpython:fix-json-uXXXX-eof-unterminatedCopy head branch name to clipboard