Fix so it compiles at least.

"make lib" takes a while, doesn't it?

Doc/lib/libitertools.tex

@@ -45,7 +45,7 @@ If needed, the tool is readily constructible using pure Python.
 
 Other tools are being considered for inclusion in future versions of the
 module.  For instance, the function
-\function{chain(\var{it0}, \var{it1}, ...})} would return elements from
+\function{chain(\var{it0}, \var{it1}, ...)} would return elements from
 the first iterator until it was exhausted and then move on to each
 successive iterator.  The module author welcomes suggestions for other
 basic building blocks.