fix small typo (bad reference to section 9.2 of the manual)

Reference: /n/sources/patch/applied/qball-man
Date: Tue Oct 23 16:13:40 CES 2012
Signed-off-by: quanstro@quanstro.net

--- /sys/man/2/qball	Tue Oct 23 16:13:31 2012
+++ /sys/man/2/qball	Tue Oct 23 16:13:29 2012
@@ -47,7 +47,7 @@
 is the orientation that
 .I redraw
 should examine, represented as a unit Quaternion (see
-.IR quaternion(9.2)).
+.IR quaternion (2)).
 The caller may set it to any orientation.
 It will be updated before each call to
 .I redraw