Remove additional empty line when output option is not specified

[scintillavoy]

👋 Hi. I'm trying out Handlebars and came across this repository.

I found results are inconsistent depending on whether the --output option is specified or not. If the option is not specified, the output has one more empty line in the end because of println!.

# This works as expected.
hbs-cli <properties file> <template file> -o <output file>

# It produces an additional empty line in the end, which is inconsistent with the above.
hbs-cli <properties file> <template file> > <output file>

I just made a small change. Thanks.

[olorin37]

Thank you for contribution.

I just found, thanks to your PR, that whole description of --outputis out-of-date😨

    /// Not implemented parameter for output file name if not provided output

While output is implemented, of course. No worries, i am intenting to rewrite CLI to clap, as after years structopt was "merged" to it, so I'll fix strings using the opportunity.

[olorin37]

I'll merge it.