Fix typos in the Lib directory as identified by codespell.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>.
(cherry picked from commit 745c9d9dfc1ad6fdfdf1d07420c6273ff67fa5be)

Co-authored-by: Christian Clauss <cclauss@me.com>

This reverts commit 58a7da9e125422323f79c4ee95ac5549989d8162.

* bpo-26680: Adds support for int.is_integer() for compatibility with float.is_integer().

The int.is_integer() method always returns True.

* bpo-26680: Adds a test to ensure that False.is_integer() and True.is_integer() are always True.

* bpo-26680: Adds Real.is_integer() with a trivial implementation using conversion to int.

This default implementation is intended to reduce the workload for subclass
implementers. It is not robust in the presence of infinities or NaNs and
may have suboptimal performance for other types.

* bpo-26680: Adds Rational.is_integer which returns True if the denominator is one.

This implementation assumes the Rational is represented in it's
lowest form, as required by the class docstring.

* bpo-26680: Adds Integral.is_integer which always returns True.

* bpo-26680: Adds tests for Fraction.is_integer called as an instance method.

The tests for the Rational abstract base class use an unbound
method to sidestep the inability to directly instantiate Rational.
These tests check that everything works correct as an instance method.

* bpo-26680: Updates documentation for Real.is_integer and built-ins int and float.

The call x.is_integer() is now listed in the table of operations
which apply to all numeric types except complex, with a reference
to the full documentation for Real.is_integer().  Mention of
is_integer() has been removed from the section 'Additional Methods
on Float'.

The documentation for Real.is_integer() describes its purpose, and
mentions that it should be overridden for performance reasons, or
to handle special values like NaN.

* bpo-26680: Adds Decimal.is_integer to the Python and C implementations.

The C implementation of Decimal already implements and uses
mpd_isinteger internally, we just expose the existing function to
Python.

The Python implementation uses internal conversion to integer
using to_integral_value().

In both cases, the corresponding context methods are also
implemented.

Tests and documentation are included.

* bpo-26680: Updates the ACKS file.

* bpo-26680: NEWS entries for int, the numeric ABCs and Decimal.

Co-authored-by: Robert Smallshire <rob@sixty-north.com>

svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r82646 | mark.dickinson | 2010-07-08 18:23:40 +0100 (Thu, 08 Jul 2010) | 1 line

  In test_decimal, convert heuristic for skipping tests into an explicit skiplist.
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  r82649 | mark.dickinson | 2010-07-08 20:03:34 +0100 (Thu, 08 Jul 2010) | 1 line

  Fix a performance issue in Decimal.pow.  Thanks Stefan Krah for finding this.
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  r82650 | mark.dickinson | 2010-07-08 20:09:16 +0100 (Thu, 08 Jul 2010) | 1 line

  Fix misplaced exactness check that was causing unnecessary work in Decimal.__pow__.
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svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r75947 | mark.dickinson | 2009-10-29 12:23:02 +0000 (Thu, 29 Oct 2009) | 20 lines

  Merged revisions 75943-75945 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r75943 | mark.dickinson | 2009-10-29 11:09:09 +0000 (Thu, 29 Oct 2009) | 1 line

    Fix duplicate test numbers in extra.decTest
  ........
    r75944 | mark.dickinson | 2009-10-29 12:04:00 +0000 (Thu, 29 Oct 2009) | 3 lines

    Issue #7233:  A number of two-argument Decimal methods were failing to
    accept ints and longs for the second argument.
  ........
    r75945 | mark.dickinson | 2009-10-29 12:11:18 +0000 (Thu, 29 Oct 2009) | 4 lines

    Issue #7233:  Fix Decimal.shift and Decimal.rotate methods for
    arguments with more digits than the current context precision.
    Bug reported by Stefan Krah.
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svn+ssh://pythondev@www.python.org/python/branches/py3k

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  r75562 | mark.dickinson | 2009-10-20 14:38:04 +0100 (Tue, 20 Oct 2009) | 10 lines

  Merged revisions 75561 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r75561 | mark.dickinson | 2009-10-20 14:33:03 +0100 (Tue, 20 Oct 2009) | 3 lines

    Issue #7099: Decimal.is_normal should return True for all nonzero
    finite non-subnormal values, even those with exponent > Emax.
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svn+ssh://pythondev@www.python.org/python/branches/py3k

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  r74566 | mark.dickinson | 2009-08-28 14:39:53 +0100 (Fri, 28 Aug 2009) | 10 lines

  Merged revisions 74564 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r74564 | mark.dickinson | 2009-08-28 14:25:02 +0100 (Fri, 28 Aug 2009) | 3 lines

    Issue #6794:  Fix handling of NaNs in Decimal.compare_total and
    Decimal.compare_total_mag.
  ........
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give correct results in the case where one argument is a quiet NaN
and the other is a finite number that requires rounding.
Thanks Mark Dickinson.