submodules

Fix invalid submodule error when using straight.el

My ordinary workflow was to start emacs with a load into my orgmode agenda, which locates me in my .emacs git-project. Upon inspecting my agenda I’ll go to some project from my todo list using helm-projectile. However, after switching to Staight.el (which does its heavy lifting with git) this workflow was broken. The result is that, when I try to use projectile from somewhere that Git includes Straight stuff, I get this failure about submodules: