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

Add description of new libmach.

man/man3/event.3

@@ -93,12 +93,12 @@ enum{
 These routines provide an interface to multiple sources of input for unthreaded
 programs.
 Threaded programs (see
-.IR thread (2))
+.IR thread (3))
 should instead use the threaded mouse and keyboard interface described
 in
-.IR mouse (2)
+.IR mouse (3)
 and
-.IR keyboard (2).
+.IR keyboard (3).
 .PP
 .I Einit
 must be called first.
@@ -113,7 +113,7 @@ the mouse and keyboard events will be enabled;
 in this case,
 .IR initdraw
 (see
-.IR graphics (2))
+.IR graphics (3))
 must have already been called.
 The user must provide a function called
 .IR eresized
@@ -123,7 +123,7 @@ is running has been resized; the argument
 is a flag specifying whether the program must call
 .I getwindow
 (see
-.IR graphics (2))
+.IR graphics (3))
 to re-establish a connection to its window.
 After resizing (and perhaps calling
 .IR getwindow ),
@@ -266,7 +266,7 @@ The return is the same as for
 .IR eread .
 .PP
 As described in
-.IR graphics (2),
+.IR graphics (3),
 the graphics functions are buffered.
 .IR Event ,
 .IR eread ,
@@ -370,7 +370,7 @@ changes the cursor image to that described by the
 .B Cursor
 .I c
 (see
-.IR mouse (2)).
+.IR mouse (3)).
 If
 .B c
 is nil, it restores the image to the default arrow.
@@ -378,7 +378,7 @@ is nil, it restores the image to the default arrow.
 .B /sys/src/libdraw
 .SH "SEE ALSO"
 .IR rio (1),
-.IR graphics (2),
-.IR plumb (2),
+.IR graphics (3),
+.IR plumb (3),
 .IR cons (3),
 .IR draw (3)