Rewrite page(2) references to page(3).

Add description of new libmach.

man/man3/wait.3

@@ -17,7 +17,7 @@ int 		await(char *s, int n)
 .SH DESCRIPTION
 .I Wait
 causes a process to wait for any child process (see
-.IR fork (2))
+.IR fork (3))
 to exit.
 It returns a
 .B Waitmsg
@@ -48,7 +48,7 @@ the time spent in system calls, and the child's elapsed real time,
 all in units of milliseconds.
 .B Msg
 contains the message that the child specified in
-.IR exits (2).
+.IR exits (3).
 For a normal exit,
 .B msg[0]
 is zero,
@@ -64,7 +64,7 @@ returns immediately, with return value nil.
 The
 .B Waitmsg
 structure is allocated by
-.IR malloc (2)
+.IR malloc (3)
 and should be freed after use.
 For programs that only need the pid of the exiting program,
 .I waitpid
@@ -83,7 +83,7 @@ The buffer filled in by
 may be parsed (after appending a NUL) using
 .IR tokenize
 (see
-.IR getfields (2));
+.IR getfields (3));
 the resulting fields are, in order, pid, the three times, and the exit string,
 which will be
 .B ''
@@ -106,8 +106,8 @@ returns
 .SH SOURCE
 .B /sys/src/libc/9syscall
 .SH "SEE ALSO"
-.IR fork (2),
-.IR exits (2),
+.IR fork (3),
+.IR exits (3),
 the
 .B wait
 file in