Doom: Disable projectile/perspective integration

doom/config.el

@@ -129,3 +129,6 @@
 ;; Insist on using regular "ls", to override Doom's insistence on "gls" on Mac+Nix
 (setq insert-directory-program "ls")
 (setq vterm-shell "fish")
+
+;; Don't create a new workspace when opening a projectile project
+(setq-default +workspaces-on-switch-project-behavior nil)