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.
diff --git a/Doc/lib/libtempfile.tex b/Doc/lib/libtempfile.tex
index e752ba4..6ed763e 100644
--- a/Doc/lib/libtempfile.tex
+++ b/Doc/lib/libtempfile.tex
@@ -50,7 +50,7 @@
 When set to a value other than \code{None}, this variable defines the
 directory in which filenames returned by \function{mktemp()} reside.
 The default is taken from the environment variable \envvar{TMPDIR}; if
-this is not set, either \file{/usr/tmp} is used (on \UNIX{}), or the
+this is not set, either \file{/usr/tmp} is used (on \UNIX), or the
 current working directory (all other systems).  No check is made to
 see whether its value is valid.
 \end{datadesc}
@@ -68,7 +68,7 @@
 prefix of the final component of the filenames returned by
 \function{mktemp()}.  A string of decimal digits is added to generate
 unique filenames.  The default is either \file{@\var{pid}.} where
-\var{pid} is the current process ID (on \UNIX{}),
+\var{pid} is the current process ID (on \UNIX),
 \file{\textasciitilde\var{pid}-} on Windows NT, \file{Python-Tmp-} on
 MacOS, or \file{tmp} (all other systems).