[#1183] Tweak a bit the project type detection order

By putting the slowest checks last we make sure that people won't have
to experience them unless all other fast type checks have failed.

See the discussion on the ticket for more details.

projectile.el

@@ -2293,6 +2293,23 @@ TEST-DIR which specifies the path to the tests relative to the project root."
 
 (define-obsolete-variable-alias 'projectile-go-function 'projectile-go-project-test-function "0.15")
 
+;;; Project type registration
+;;
+;; Project type detection happens in a reverse order with respect to
+;; project type registration (invocations of `projectile-register-project-type').
+;;
+;; As function-based project type detection is pretty slow, so it
+;; should be tried at the end if everything else failed (meaning here
+;; it should be listed first).
+;;
+;; Ideally common project types should be checked earlier than exotic ones.
+(projectile-register-project-type 'haskell-cabal #'projectile-cabal-project-p
+                                  :compile "cabal build"
+                                  :test "cabal test")
+(projectile-register-project-type 'go projectile-go-project-test-function
+                                  :compile "go build ./..."
+                                  :test "go test ./...")
+;; File-based project types
 (projectile-register-project-type 'emacs-cask '("Cask")
                                   :compile "cask install")
 (projectile-register-project-type 'symfony '("composer.json" "app" "src" "vendor")
@@ -2358,18 +2375,12 @@ TEST-DIR which specifies the path to the tests relative to the project root."
 (projectile-register-project-type 'haskell-stack '("stack.yaml")
                                   :compile "stack build"
                                   :test "stack build --test")
-(projectile-register-project-type 'haskell-cabal #'projectile-cabal-project-p
-                                  :compile "cabal build"
-                                  :test "cabal test")
 (projectile-register-project-type 'rust-cargo '("Cargo.toml")
                                   :compile "cargo build"
                                   :test "cargo test")
 (projectile-register-project-type 'r '("DESCRIPTION")
                                   :compile "R CMD INSTALL --with-keep.source ."
                                   :test (concat "R CMD check -o " temporary-file-directory " ."))
-(projectile-register-project-type 'go projectile-go-project-test-function
-                                  :compile "go build ./..."
-                                  :test "go test ./...")
 (projectile-register-project-type 'racket '("info.rkt")
                                   :test "raco test .")
 (projectile-register-project-type 'elixir '("mix.exs")
@@ -2387,8 +2398,6 @@ TEST-DIR which specifies the path to the tests relative to the project root."
                                   :configure "cmake %s"
                                   :compile "cmake --build ."
                                   :test "ctest")
-
-;; Project detection goes in reverse order of registration.
 ;; Rails needs to be registered after npm, otherwise `package.json` makes it `npm`.
 ;; https://github.com/bbatsov/projectile/pull/1191
 (projectile-register-project-type 'rails-test '("Gemfile" "app" "lib" "db" "config" "test")