remove some wacky Xo/Xc;

src/lib/libc/stdlib/strtod.3

@@ -29,9 +29,9 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: strtod.3,v 1.15 2012/09/15 11:47:04 martynas Exp $
+.\"	$OpenBSD: strtod.3,v 1.16 2012/09/16 17:54:03 jmc Exp $
 .\"
-.Dd $Mdocdate: September 15 2012 $
+.Dd $Mdocdate: September 16 2012 $
 .Dt STRTOD 3
 .Os
 .Sh NAME
@@ -95,7 +95,7 @@ or
 ignoring case, it is interpreted as an infinity or a quiet \*(Na,
 respectively.
 The syntax
-.Dq Xo Pf NAN( Ar "s" ) Xc ,
+.Dq NAN Ns Pq Ar s ,
 where
 .Ar s
 is an alphanumeric string, produces the same value as the call