Minor issue: enabling project.el integration requires requiring projectile

[misha-ridge]

Expected behavior

(with-eval-after-load 'project
  (add-hook 'project-find-functions #'project-projectile))

will cause Projectile to load whenever project.el is loaded

Actual behavior

Symbol’s function definition is void: project-projectile

Steps to reproduce the problem

• Install, but do not require Projectile.
• Eval the snippet above.
• Eval (project-current)

Suggested fix

Make project-projectile autoloadable.

Environment & Version information

Projectile version information

Projectile 2.8.0-snapshot

Emacs version

GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.33, cairo version 1.16.0) of 2023-05-01

Operating system

Ubuntu 22.04