#59009: Added document and a test case for newlines_in_values case.

[wooseogchoi]

• [x ] closes BUG: Reading large CSV files with pyarrow when values contain newline character. #59009 (Replace xxxx with the GitHub issue number)
• [ x] Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[yuanx749]

Suggested change

	>>> from pyarrow import csv
	>>> parse_options = csv.ParseOptions(newlines_in_values=True)
	>>> table = csv.read_csv("example.csv", parse_options=parse_options)
	>>> import io
	>>> from pyarrow import csv
	>>> rows = [{"text": "ab\ncd", "idx": idx} for idx in range(1_000_000)]
	>>> df = pd.DataFrame(rows)
	>>> source = io.BytesIO(df.to_string(index=False).encode())
	>>> parse_options = csv.ParseOptions(newlines_in_values=True)
	>>> table = csv.read_csv(source, parse_options=parse_options)

The doctest will fail because "example.csv" does not exist. We can change a bit or just skip the test.