undocument printf(1), it causes user confusion

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.420 2016/11/11 23:31:36 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.421 2017/02/17 20:38:16 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.160 2015/07/04 13:27:04 feinerer Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
@@ -76,7 +76,7 @@
 .\" with -mandoc, it might implement .Mx itself, but we want to
 .\" use our own definition. And .Dd must come *first*, always.
 .\"
-.Dd $Mdocdate: November 11 2016 $
+.Dd $Mdocdate: February 17 2017 $
 .\"
 .\" Check which macro package we use, and do other -mdoc setup.
 .\"
@@ -3823,20 +3823,6 @@ As above, the
 .Fl n
 option suppresses the trailing newline.
 .Pp
-.It Ic printf Ar format Op Ar arguments ...
-Formatted output.
-Approximately the same as the
-.Xr printf 1 ,
-utility, except it uses the same
-.Sx Backslash expansion
-and I/O code and does not handle floating point as the rest of
-.Nm mksh .
-An external utility is preferred over the builtin.
-This is not normally part of
-.Nm mksh ;
-however, distributors may have added this as builtin as a speed hack.
-Do not use in new code.
-.Pp
 .It Ic pwd Op Fl LP
 Print the present working directory.
 If the