minor grammar fixes to exceptions.rst

Author: gpshead

Doc/library/exceptions.rst

@@ -419,13 +419,13 @@ The following exceptions are the exceptions that are usually raised.
 .. exception:: PythonFinalizationError
 
  This exception is derived from :exc:`RuntimeError`. It is raised when
- an operations is blocked during the :term:`Python finalization <interpreter
- shutdown>`.
+ an operation is blocked during interpreter shutdown also known as
+ :term:`Python finalization <interpreter shutdown>`.
 
  Examples of operations which can be blocked with a
  :exc:`PythonFinalizationError` during the Python finalization:
 
- * create a new Python thread;
+ * Creating a new Python thread.
  * :func:`os.fork`.
 
  See also the :func:`sys.is_finalizing` function.