Added \label{} for logical addressing.

Logical markup.

Doc/lib/libpython.tex

 \chapter{Python Services}
+\label{python}
 
 The modules described in this chapter provide a wide range of services
 related to the Python interpreter and its interaction with its
@@ -26,7 +27,7 @@ environment.  Here's an overview:
 --- Convert Python objects to streams of bytes and back.
 
 \item[copy_reg]
---- Register \code{pickle} support functions.
+--- Register \module{pickle} support functions.
 
 \item[shelve]
 --- Python object persistency.
@@ -39,7 +40,7 @@ environment.  Here's an overview:
 different constraints).
 
 \item[imp]
---- Access the implementation of the \code{import} statement.
+--- Access the implementation of the \keyword{import} statement.
 
 \item[ni]
 --- New import (obsolete).

Doc/lib/libsomeos.tex

 \chapter{Optional Operating System Services}
+\label{someos}
 
 The modules described in this chapter provide interfaces to operating
 system features that are available on selected operating systems only.
-The interfaces are generally modelled after the \UNIX{} or C
+The interfaces are generally modelled after the \UNIX{} or \C{}
 interfaces but they are available on some other systems as well
 (e.g. Windows or NT).  Here's an overview:
 
@@ -32,7 +33,7 @@ interfaces but they are available on some other systems as well
 \item[zlib]
 \item[gzip]
 --- Compression and decompression compatible with the
-\code{gzip} program (zlib is the low-level interface, gzip the
-high-level one).
+\program{gzip} program (\module{zlib} is the low-level interface,
+\module{gzip} the high-level one).
 
 \end{description}

Doc/libpython.tex

 \chapter{Python Services}
+\label{python}
 
 The modules described in this chapter provide a wide range of services
 related to the Python interpreter and its interaction with its
@@ -26,7 +27,7 @@ environment.  Here's an overview:
 --- Convert Python objects to streams of bytes and back.
 
 \item[copy_reg]
---- Register \code{pickle} support functions.
+--- Register \module{pickle} support functions.
 
 \item[shelve]
 --- Python object persistency.
@@ -39,7 +40,7 @@ environment.  Here's an overview:
 different constraints).
 
 \item[imp]
---- Access the implementation of the \code{import} statement.
+--- Access the implementation of the \keyword{import} statement.
 
 \item[ni]
 --- New import (obsolete).

Doc/libsomeos.tex

 \chapter{Optional Operating System Services}
+\label{someos}
 
 The modules described in this chapter provide interfaces to operating
 system features that are available on selected operating systems only.
-The interfaces are generally modelled after the \UNIX{} or C
+The interfaces are generally modelled after the \UNIX{} or \C{}
 interfaces but they are available on some other systems as well
 (e.g. Windows or NT).  Here's an overview:
 
@@ -32,7 +33,7 @@ interfaces but they are available on some other systems as well
 \item[zlib]
 \item[gzip]
 --- Compression and decompression compatible with the
-\code{gzip} program (zlib is the low-level interface, gzip the
-high-level one).
+\program{gzip} program (\module{zlib} is the low-level interface,
+\module{gzip} the high-level one).
 
 \end{description}