Remove jane_street version

It's not used. We'll re-add it if really necessary.

doc/project-layout-specification.rst

@@ -16,16 +16,9 @@ executable using ``modules``.
 The next sections describe the format of Jbuilder metadata files.
 
 Note that the Jbuilder metadata format is versioned in order to ensure
-forward compatibility. Jane Street packages use a special
-``jane_street`` version which correspond to a rolling and unstable
-version that follows the internal Jane Street development. You shouldn't
-use this in your project, it is only intended to make the publication of
-Jane Street packages easier.
-
-Except for the special ``jane_street`` version, there is currently only
-one version available, but to be future proof, you should still specify
-it in your ``jbuild`` files. If no version is specified, the latest one
-will be used.
+forward compatibility. There is currently only one version available,
+but to be future proof, you should still specify it in your ``jbuild``
+files. If no version is specified, the latest one will be used.
 
 Metadata format
 ===============

src/jbuild_types.ml

@@ -11,12 +11,10 @@ open Sexp.Of_sexp
 module Jbuild_version = struct
   type t =
     | V1
-    | Vjs
 
   let t =
     enum
       [ "1", V1
-      ; "jane_street", Vjs
       ]
 
   let latest_stable = V1
@@ -945,7 +943,6 @@ module Stanza = struct
 
   let select : Jbuild_version.t -> Pkgs.t -> t list Sexp.Of_sexp.t = function
     | V1  -> v1
-    | Vjs -> v1
 end
 
 module Stanzas = struct