Make all the \seemodule explanations consistent: start with a capitalized
letter and end with proper punctuation.  "Documenting Python" will be
updated accordingly so that this will be editorial policy for the Python
documentation.
diff --git a/Doc/lib/libgzip.tex b/Doc/lib/libgzip.tex
index 3df75ce..34ec897 100644
--- a/Doc/lib/libgzip.tex
+++ b/Doc/lib/libgzip.tex
@@ -65,5 +65,6 @@
 \end{funcdesc}
 
 \begin{seealso}
-\seemodule{zlib}{the basic data compression module}
+  \seemodule{zlib}{The basic data compression module needed to support
+                   the \program{gzip} file format.}
 \end{seealso}