Patch #1015012. Improve markup and punctuation in libsocket.tex

Doc/lib/libsocket.tex

@@ -305,10 +305,10 @@ success, a new \class{SSLObject} is returned.
 
 \begin{funcdesc}{socketpair}{\optional{family\optional{, type\optional{, proto}}}}
 Build a pair of connected socket objects using the given address
-family, socket type and protocol number.  Address family, socket type
+family, socket type, and protocol number.  Address family, socket type,
 and protocol number are as for the \function{socket()} function above.
-The default family is AF_UNIX if defined for the platform, otherwise
-the default is AF_INET.
+The default family is \constant{AF_UNIX} if defined on the platform;
+otherwise, the default is \constant{AF_INET}.
 Availability: \UNIX.  \versionadded{2.4}
 \end{funcdesc}
 

Modules/socketmodule.c

@@ -2981,7 +2981,7 @@ Return the protocol number for the named protocol.  (Rarely used.)");
 #ifdef HAVE_SOCKETPAIR
 /* Create a pair of sockets using the socketpair() function.
    Arguments as for socket() except the default family is AF_UNIX if
-   defined for the platform, otherwise the default is AF_INET. */
+   defined on the platform; otherwise, the default is AF_INET. */
 
 /*ARGSUSED*/
 static PyObject *
@@ -3029,7 +3029,7 @@ PyDoc_STRVAR(socketpair_doc,
 Create a pair of socket objects from the sockets returned by the platform\n\
 socketpair() function.\n\
 The arguments are the same as for socket() except the default family is\n\
-AF_UNIX if defined for the platform, otherwise the default is AF_INET.");
+AF_UNIX if defined on the platform; otherwise, the default is AF_INET.");
 
 #endif /* HAVE_SOCKETPAIR */