Describe the bug

When formatting an empty file with ocamlformat, it append a trailing line.

How to Reproduce

$ touch ~/tmp/empty.ml
$ ocamlformat --enable-outside-detected-project -i ~/tmp/empty.ml

empty.ml ends up with an extra line in it. wc -l empty.ml shows different counts before and after formatting.

Tested against ocamlformat at e94fa81.