DOC: document doublequote in read_csv

Title is self-explanatory.

Author: gfyoung <[email protected]>

Closes #13368 from gfyoung/doublequote-doc and squashes the following commits:

f3e01fc [gfyoung] DOC: document doublequote in read_csv

Author: gfyoung

doc/source/io.rst

@@ -273,6 +273,10 @@ quoting : int or ``csv.QUOTE_*`` instance, default ``None``
   ``QUOTE_MINIMAL`` (0), ``QUOTE_ALL`` (1), ``QUOTE_NONNUMERIC`` (2) or
   ``QUOTE_NONE`` (3). Default (``None``) results in ``QUOTE_MINIMAL``
   behavior.
+doublequote : boolean, default ``True``
+   When ``quotechar`` is specified and ``quoting`` is not ``QUOTE_NONE``,
+   indicate whether or not to interpret two consecutive ``quotechar`` elements
+   **inside** a field as a single ``quotechar`` element.
 escapechar : str (length 1), default ``None``
   One-character string used to escape delimiter when quoting is ``QUOTE_NONE``.
 comment : str, default ``None``

pandas/io/parsers.py

@@ -192,6 +192,10 @@
     Control field quoting behavior per ``csv.QUOTE_*`` constants. Use one of
     QUOTE_MINIMAL (0), QUOTE_ALL (1), QUOTE_NONNUMERIC (2) or QUOTE_NONE (3).
     Default (None) results in QUOTE_MINIMAL behavior.
+doublequote : boolean, default ``True``
+   When quotechar is specified and quoting is not ``QUOTE_NONE``, indicate
+   whether or not to interpret two consecutive quotechar elements INSIDE a
+   field as a single ``quotechar`` element.
 escapechar : str (length 1), default None
     One-character string used to escape delimiter when quoting is QUOTE_NONE.
 comment : str, default None