Backport: * lisp/files.el: Remove support for extra .dir-locals file

(dir-locals-file-2, dir-locals--all-files): Remove.
(dir-locals-collect-variables, dir-locals-file, dir-locals-find-file)
(dir-locals-read-from-file, hack-dir-local-variables): Revert changes.

* lisp/files-x.el (modify-dir-local-variable): Revert changes.

* lisp/help-fns.el (describe-variable): Revert changes.

* doc/emacs/custom.texi (Directory Variables): Revert changes.

* etc/NEWS: Revert changes.

1 files changed, 0 insertions, 4 deletions

diff --git a/etc/NEWS b/etc/NEWS
index d0415a22f95..a7348e4e6f2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -181,10 +181,6 @@ by default, and must be enabled by using the `--with-modules' option
 at configure time.
 
 +++
-** A second dir-local file (.dir-locals-2.el) is now accepted.
-See the variable `dir-locals-file-2' for more information.
-
-+++
 ** Network security (TLS/SSL certificate validity and the like) is
 added via the new Network Security Manager (NSM) and controlled via
 the `network-security-level' variable.