Update fcntl doc: replace IOError with OSError

Issue #26716. IOError is a deprecated alias to OSError since Python 3.3.

Doc/library/fcntl.rst

@@ -83,7 +83,7 @@ The module defines the following functions:
    buffer 1024 bytes long which is then passed to :func:`ioctl` and copied back
    into the supplied buffer.
 
-   If the :c:func:`ioctl` fails, an :exc:`IOError` exception is raised.
+   If the :c:func:`ioctl` fails, an :exc:`OSError` exception is raised.
 
    An example::
 
@@ -106,7 +106,7 @@ The module defines the following functions:
    :manpage:`flock(2)` for details.  (On some systems, this function is emulated
    using :c:func:`fcntl`.)
 
-   If the :c:func:`flock` fails, an :exc:`IOError` exception is raised.
+   If the :c:func:`flock` fails, an :exc:`OSError` exception is raised.
 
 
 .. function:: lockf(fd, cmd, len=0, start=0, whence=0)

Modules/fcntlmodule.c

@@ -344,7 +344,7 @@ of the following values:
 
 When operation is LOCK_SH or LOCK_EX, it can also be bitwise ORed with
 LOCK_NB to avoid blocking on lock acquisition.  If LOCK_NB is used and the
-lock cannot be acquired, an IOError will be raised and the exception will
+lock cannot be acquired, an OSError will be raised and the exception will
 have an errno attribute set to EACCES or EAGAIN (depending on the operating
 system -- for portability, check for either value).