DOC: actually document float_precision in read_csv

[ci skip]

Author: gfyoung

doc/source/io.rst

@@ -269,6 +269,10 @@ thousands : str, default ``None``
   Thousands separator.
 decimal : str, default ``'.'``
   Character to recognize as decimal point. E.g. use ``','`` for European data.
+float_precision : string, default None
+  Specifies which converter the C engine should use for floating-point values.
+  The options are ``None`` for the ordinary converter, ``high`` for the
+  high-precision converter, and ``round_trip`` for the round-trip converter.
 lineterminator : str (length 1), default ``None``
   Character to break file into lines. Only valid with C parser.
 quotechar : str (length 1)

pandas/io/parsers.py

@@ -183,6 +183,11 @@
     Thousands separator
 decimal : str, default '.'
     Character to recognize as decimal point (e.g. use ',' for European data).
+float_precision : string, default None
+    Specifies which converter the C engine should use for floating-point
+    values. The options are `None` for the ordinary converter,
+    `high` for the high-precision converter, and `round_trip` for the
+    round-trip converter.
 lineterminator : str (length 1), default None
     Character to break file into lines. Only valid with C parser.
 quotechar : str (length 1), optional