gh-128067: Add newline to new REPL output when needed to avoid chopping characters #131011
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This PR attempts to fix #128067 (and #128809) by capturing REPL output into a
StringIO, checking whether it ends in a newline and adding one if necessary. Works on Windows and Linux.Before:
After:
Feel free to suggest improvements. If this approach doesn't make sense, I have no great attachment to this PR.