Capitalize & use periods for \seemodule explanation parameter.

Doc/lib/libpickle.tex

@@ -282,14 +282,14 @@ This exception is raised when an unpicklable object is passed to
 
 
 \begin{seealso}
-  \seemodule[copyreg]{copy_reg}{pickle interface constructor
-                                registration}
+  \seemodule[copyreg]{copy_reg}{Pickle interface constructor
+                                registration for extension types.}
 
-  \seemodule{shelve}{indexed databases of objects; uses \module{pickle}}
+  \seemodule{shelve}{Indexed databases of objects; uses \module{pickle}.}
 
-  \seemodule{copy}{shallow and deep object copying}
+  \seemodule{copy}{Shallow and deep object copying.}
 
-  \seemodule{marshal}{high-performance serialization of built-in types}
+  \seemodule{marshal}{High-performance serialization of built-in types.}
 \end{seealso}