Document the dbhash module, and link to it from appropriate places.
diff --git a/Doc/lib/libshelve.tex b/Doc/lib/libshelve.tex
index 6b96872..de8e04c 100644
--- a/Doc/lib/libshelve.tex
+++ b/Doc/lib/libshelve.tex
@@ -66,7 +66,7 @@
\begin{seealso}
\seemodule{anydbm}{Generic interface to \code{dbm}-style databases.}
- % Should include entry for dbhash, but that isn't documented.
+ \seemodule{dbhash}{BSD \code{db} database interface.}
\seemodule{dbm}{Standard \UNIX{} database interface.}
\seemodule{dumbdbm}{Portable implementation of the \code{dbm} interface.}
\seemodule{gdbm}{GNU database interface, based on the \code{dbm} interface.}