Use -F instead of -f in tail(1) examples

[0mp]

Summary

Commit message:

Use -F instead of -f in tail(1) examples

There is an example in tail(1) manual page explaining how to use tail(1) to
track the contents of /var/log/messages. The example uses the -f flag to follow
the file. The problem with the -f flag is that it cannot handle the situation
where /var/log/messages is rotated. Hence, use -F instead in the example.

[asomers]

LGTM, but since the reader already has the man page open, you probably don't need to explain the`-F` flag again.

[0mp]

Thanks, @asomers!