Fix typo noticed by Tom Lynn.

Doc/library/time.rst

@@ -309,7 +309,7 @@ The module defines the following functions and data items:
 
    On Windows versions older than Vista, :func:`monotonic` detects
    :c:func:`GetTickCount` integer overflow (32 bits, roll-over after 49.7 days).
-   It increases an internal epoch (reference time by) 2\ :sup:`32` each time
+   It increases an internal epoch (reference time) by 2\ :sup:`32` each time
    that an overflow is detected.  The epoch is stored in the process-local state
    and so the value of :func:`monotonic` may be different in two Python
    processes running for more than 49 days. On more recent versions of Windows