zfs-diff.8 missing argument in -F description

[melak]

System information

N/A (Git HEAD)

Describe the problem you're observing

man zfs-diff renders as

 -F  Display an indication of the type of file, in a manner similar to
     the - option of ls(1).

There is a missing F flag argument to the Fl macro in man/man8/zfs-diff.8:

--- a/man/man8/zfs-diff.8
+++ b/man/man8/zfs-diff.8
@@ -66,7 +66,7 @@ R       The path has been renamed
 .Bl -tag -width "-F"
 .It Fl F
 Display an indication of the type of file, in a manner similar to the
-.Fl
+.Fl F
 option of
 .Xr ls 1 .
 .Bd -literal

Describe how to reproduce the problem

Run man zfs-diff, read description for -F.

@melak would you like to open a pull request for this change?