Fix minor docs markup errors.

Doc/library/decimal.rst

@@ -236,7 +236,7 @@ For more advanced work, it may be useful to create alternate contexts using the
 Context() constructor.  To make an alternate active, use the :func:`setcontext`
 function.
 
-In accordance with the standard, the :mod:`Decimal` module provides two ready to
+In accordance with the standard, the :mod:`decimal` module provides two ready to
 use standard contexts, :const:`BasicContext` and :const:`ExtendedContext`. The
 former is especially useful for debugging because many of the traps are
 enabled:

Doc/library/profile.rst

@@ -663,7 +663,7 @@ you are using :class:`profile.Profile` or :class:`cProfile.Profile`,
 
       pr = cProfile.Profile(your_integer_time_func, 0.001)
 
-   As the :mod:`cProfile.Profile` class cannot be calibrated, custom timer
+   As the :class:`cProfile.Profile` class cannot be calibrated, custom timer
    functions should be used with care and should be as fast as possible.  For
    the best results with a custom timer, it might be necessary to hard-code it
    in the C source of the internal :mod:`_lsprof` module.

Doc/tutorial/datastructures.rst

@@ -179,9 +179,9 @@ There are three built-in functions that are very useful when used with lists:
 
 ``filter(function, sequence)`` returns a sequence consisting of those items from
 the sequence for which ``function(item)`` is true. If *sequence* is a
-:class:`string` or :class:`tuple`, the result will be of the same type;
-otherwise, it is always a :class:`list`. For example, to compute a sequence of
-numbers divisible by 3 or 5::
+:class:`str`, :class:`unicode` or :class:`tuple`, the result will be of the
+same type; otherwise, it is always a :class:`list`.  For example, to compute a
+sequence of numbers divisible by 3 or 5::
 
    >>> def f(x): return x % 3 == 0 or x % 5 == 0
    ...