Update documentation of '.dir-locals-2.el'

See https://lists.gnu.org/r/emacs-devel/2017-11/msg00649.html
for more details.
* lisp/files.el (dir-locals-file-2): Remove unused constant.
* lisp/files.el (dir-locals-file): Mention ".dir-locals-2.el" in
the doc string.
* doc/lispref/variables.texi (Directory Local Variables): Mention
".dir-locals-2.el".
* etc/NEWS: Replace `dir-locals-file-2' mention with
`dir-locals-file'.

1 files changed, 9 insertions, 9 deletions

diff --git a/lisp/files.el b/lisp/files.el
index d8b38a9f169..8021e1bbed5 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -3905,16 +3905,16 @@ VARIABLES list of the class.  The list is processed in order.
   "File that contains directory-local variables.
 It has to be constant to enforce uniform values across different
 environments and users.
-See also `dir-locals-file-2', whose values override this one's.
-See Info node `(elisp)Directory Local Variables' for details.")
 
-(defconst dir-locals-file-2 ".dir-locals-2.el"
-  "File that contains directory-local variables.
-This essentially a second file that can be used like
-`dir-locals-file', so that users can have specify their personal
-dir-local variables even if the current directory already has a
-`dir-locals-file' that is shared with other users (such as in a
-git repository).
+A second dir-locals file can be used by a user to specify their
+personal dir-local variables even if the current directory
+already has a `dir-locals-file' that is shared with other
+users (such as in a git repository).  The name of this second
+file is derived by appending \"-2\" to the base name of
+`dir-locals-file'.  With the default value of `dir-locals-file',
+a \".dir-locals-2.el\" file in the same directory will override
+the \".dir-locals.el\".
+
 See Info node `(elisp)Directory Local Variables' for details.")
 
 (defun dir-locals--all-files (directory)