DOC: Document how encoding errors are handled (#39492)

Author: twoertwein

pandas/io/parsers/readers.py

@@ -270,6 +270,11 @@
     Encoding to use for UTF when reading/writing (ex. 'utf-8'). `List of Python
     standard encodings
     <https://docs.python.org/3/library/codecs.html#standard-encodings>`_ .
+    .. versionchanged:: 1.2
+
+       When ``encoding`` is ``None``, ``errors="replace"`` is passed to
+       ``open()``. Otherwise, ``errors="strict"`` is passed to ``open()``.
+       This behavior was previously only the case for ``engine="python"``.
 dialect : str or csv.Dialect, optional
     If provided, this parameter will override values (default or not) for the
     following parameters: `delimiter`, `doublequote`, `escapechar`,