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/lib/libamoeba.tex

@@ -123,7 +123,7 @@ Returns the standard info string of the object.
 \end{funcdesc}
 
 \begin{funcdesc}{tod_gettime}{}
-Returns the time (in seconds since the Epoch, in UCT, as for \POSIX{}) from
+Returns the time (in seconds since the Epoch, in UCT, as for \POSIX) from
 a time server.
 \end{funcdesc}