bintrans(1): fix typo

Reported by:	Helge Oldach <[email protected]>

Author: bapt

usr.bin/bintrans/bintrans.1

@@ -236,7 +236,7 @@ Decode.
 Output to
 .Ar output_file
 instead of standard output.
-.It fl r
+.It Fl r
 Encode/Decode in RFC2047 specific variant.
 .El
 .Sh EXAMPLES