fix manpages

chmod.1

@@ -3,7 +3,7 @@
 chmod \- change file mode
 .SH SYNOPSIS
 .B chmod
-.RB [ -Rr ]
+.RB [ \-Rr ]
 .RI mode
 .RI [ file ...]
 .SH DESCRIPTION
@@ -18,7 +18,7 @@ third defines permissions for others in the file's group; and the fourth for all
 other users. Leading zeroes may be omitted.
 .SH OPTIONS
 .TP
-.B -R, -r
+.B \-R, \-r
 change directory mode recursively.
 .SH SEE ALSO
 .IR chmod (2)