event/ServerSocket, doc, ...: refer to AF_LOCAL as "local socket"

.. and not "UNIX domain socket.  Be consistent about the naming.

src/net/SocketUtil.cxx

@@ -35,7 +35,7 @@ socket_bind_listen(int domain, int type, int protocol,
 		throw MakeSocketError("Failed to create socket");
 
 #ifdef HAVE_UN
-	if (domain == AF_UNIX) {
+	if (domain == AF_LOCAL) {
 		/* Prevent access until right permissions are set */
 		fchmod(fd.Get(), 0);
 	}

src/net/SocketUtil.hxx

@@ -32,7 +32,7 @@ class SocketAddress;
 /**
  * Creates a socket listening on the specified address.  This is a
  * shortcut for socket(), bind() and listen().
- * When a unix socket is created (domain == AF_UNIX), its
+ * When a local socket is created (domain == AF_LOCAL), its
  * permissions will be stripped down to prevent unauthorized
  * access. The caller is responsible to apply proper permissions
  * at a later point.

src/net/ToString.cxx

@@ -106,7 +106,7 @@ ToString(SocketAddress address) noexcept
 {
 #ifdef HAVE_UN
 	if (address.GetFamily() == AF_LOCAL)
-		/* return path of UNIX domain sockets */
+		/* return path of local socket */
 		return LocalAddressToString(*(const sockaddr_un *)address.GetAddress(),
 					    address.GetSize());
 #endif