quote value ending with multi-character delimiter prefix

[rootvector2]

printWithQuotes in MINIMAL quote mode does not encapsulate a value whose tail is a straddling prefix of a multi-character delimiter, so the printed record cannot be read back. With delimiter ||, a field ending in | such as a| is written unquoted, and the record a|||b is then parsed by CSVParser as [a, |b] because the greedy lexer matches the delimiter one character early at the value/delimiter boundary. The existing scan only quotes when the full delimiter occurs inside the value; a trailing partial delimiter slips through. Fixed by endsWithDelimiterPrefix, which quotes the value when appending the delimiter after it would create a boundary-straddling delimiter match. Single-character delimiters and values that contain the delimiter start without a straddling suffix (for example delimiter [|], value a[) are unaffected.

Found while auditing multi-character delimiter round-trips through the printer.

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