Clean up some markup cruft. A number of the macros that take no

parameters (like \UNIX) are commonly entered using an empty group to
separate the markup from a following inter-word space; this is not
needed when the next character is punctuation, or the markup is the
last thing in the enclosing group.  These cases were marked
inconsistently; the empty group is now *only* used when needed.

Doc/api/abstract.tex

@@ -736,14 +736,14 @@ determination.
 
 \begin{cfuncdesc}{PyObject*}{PySequence_Fast_GET_ITEM}{PyObject *o, int i}
   Return the \var{i}th element of \var{o}, assuming that \var{o} was
-  returned by \cfunction{PySequence_Fast()}, \var{o} is not \NULL{},
+  returned by \cfunction{PySequence_Fast()}, \var{o} is not \NULL,
   and that \var{i} is within bounds.
 \end{cfuncdesc}
 
 \begin{cfuncdesc}{int}{PySequence_Fast_GET_SIZE}{PyObject *o}
   Returns the length of \var{o}, assuming that \var{o} was
   returned by \cfunction{PySequence_Fast()} and that \var{o} is
-  not \NULL{}.  The size can also be gotten by calling
+  not \NULL.  The size can also be gotten by calling
   \cfunction{PySequence_Size()} on \var{o}, but
   \cfunction{PySequence_Fast_GET_SIZE()} is faster because it can
   assume \var{o} is a list or tuple.

Doc/api/intro.tex

@@ -3,7 +3,7 @@
 
 The Application Programmer's Interface to Python gives C and
 \Cpp{} programmers access to the Python interpreter at a variety of
-levels.  The API is equally usable from \Cpp{}, but for brevity it is
+levels.  The API is equally usable from \Cpp, but for brevity it is
 generally referred to as the Python/C API.  There are two
 fundamentally different reasons for using the Python/C API.  The first
 reason is to write \emph{extension modules} for specific purposes;