Fix the problem addressed by patch

[ 819012 ] Fix for former/latter confusion in Extending documentation

although not by using supplied patch.

Doc/ext/extending.tex

@@ -819,7 +819,7 @@ dynamic allocation and deallocation of memory on the heap.  In C,
 this is done using the functions \cfunction{malloc()} and
 \cfunction{free()}.  In \Cpp, the operators \keyword{new} and
 \keyword{delete} are used with essentially the same meaning and
-we'll restrict the following discussion to the latter.
+we'll restrict the following discussion to the C case.
 
 Every block of memory allocated with \cfunction{malloc()} should
 eventually be returned to the pool of available memory by exactly one