Edit description a bit
diff --git a/Doc/lib/libitertools.tex b/Doc/lib/libitertools.tex
index 82912b0..cd867b0 100644
--- a/Doc/lib/libitertools.tex
+++ b/Doc/lib/libitertools.tex
@@ -132,9 +132,9 @@
\begin{funcdesc}{groupby}{iterable\optional{, key}}
Make an iterator that returns consecutive keys and groups from the
- \var{iterable}. \var{key} is function computing a key value for each
+ \var{iterable}. \var{key} is a function computing a key value for each
element. If not specified or is \code{None}, \var{key} defaults to an
- identity function (returning the element unchanged). Generally, the
+ identity function and returns the element unchanged. Generally, the
iterable needs to already be sorted on the same key function.
The returned group is itself an iterator that shares the underlying