Make the module docstring a raw string, so that the backslash in

"read until end of line ('\n') or EOF" will be treated literally.
Fixes SF bug #860155.

Lib/StringIO.py

-"""File-like objects that read from or write to a string buffer.
+r"""File-like objects that read from or write to a string buffer.
 
 This implements (nearly) all stdio methods.