bindfs.1: add section for --delete-filtered

src/bindfs.1

@@ -174,6 +174,14 @@ to distinguish specifier parts, e.g. \fIa:pci:0000:00:00/...\fP,
 where \fIa\fP is an "any type" specifier and \fIpci:0000:00:00\fP is
 a file name.
 
+.TP
+.B \-\-delete\-filtered
+When removing a directory, also transparently remove hidden with
+\fB\-\-file\-filter\fP files in it. If this option not active,
+such directories won't remove with \fBENOTEMPTY\fP error. If a directory
+contains hidden directories, they will be deleted recursively, as with
+\fBrm -rf\fP command. If \fB\-\-resolve\-symlinks\fP is active, hidden
+files in resolved directories will not be removed.
 
 .SH CHOWN/CHGRP POLICY
 The behaviour on chown/chgrp calls can be changed. By default they are passed