Quickstart does not mention _build is created by dune init proj project_name

[johnwhitington]

For example:

$ dune init proj foo
Entering directory '/Users/john/Desktop/foo'
Success: initialized project component named foo
$ cd foo
$ ls
_build		dune-project	lib
bin		foo.opam	test

Why does it create _build anyway? It's odd that dune init proj followed by dune clean results in fewer files. It might also cause a beginner to erroneously check _build into their version control system. Perhaps the behaviour should be removed, so it matches what QuickStart says:

https://dune.readthedocs.io/en/stable/quick-start.html

Specifications

• Version of dune (output of dune --version): 3.14.0
• Version of ocaml (output of ocamlc --version): 4.14.2+dev0-2022-12-19
• Operating system (distribution and version): MacOS Sonoma