Fix editorconfig-display-current-properties

In Emacs-30, `editorconfig-display-current-properties` was
broken in that it displayed only the properties set by
`editorconfig-apply` but not those set in the "normal" way,
i.e. by `hack-local-variables`.  Fix that along with a few
docstrings that had misleading old info.

* lisp/editorconfig-tools.el (editorconfig-apply)
(editorconfig-mode-apply): Fix docstring and declare obsolete.

* lisp/editorconfig.el (editorconfig-properties-hash):
(editorconfig-call-get-properties-function): Remove elements of
docstring that aren't true any more.
(editorconfig-call-get-properties-function):
Set `editorconfig-properties-hash`.

etc/NEWS

@@ -857,6 +857,12 @@ you could already use 'C-u C-x C-n' to clear the goal column.
 
 * Changes in Specialized Modes and Packages in Emacs 31.1
 
+** Editorconfig
+---
+*** 'editorconfig-apply' is declared obsolete.
+You can now use 'editorconfig-display-current-properties' without having
+to call 'editorconfig-apply'.
+
 ** Auth Source
 
 +++

lisp/editorconfig-tools.el

@@ -41,11 +41,8 @@
 
 ;;;###autoload
 (defun editorconfig-apply ()
-  "Get and apply EditorConfig properties to current buffer.
+  "Get and apply EditorConfig properties to current buffer."
-
+  (declare (obsolete hack-local-variables "31.1"))
-This function does not respect the values of `editorconfig-exclude-modes' and
-`editorconfig-exclude-regexps' and always applies available properties.
-Use `editorconfig-mode-apply' instead to make use of these variables."
   (interactive)
   (when buffer-file-name
     (condition-case err
@@ -76,14 +73,12 @@ Use `editorconfig-mode-apply' instead to make use of these variables."
                         :error)))))
 
 (defun editorconfig-mode-apply ()
-  "Get and apply EditorConfig properties to current buffer.
+  "Get and apply EditorConfig properties to current buffer."
-
+  (declare (obsolete editorconfig-apply "31.1"))
-This function does nothing when the major mode is listed in
-`editorconfig-exclude-modes', or variable `buffer-file-name' matches
-any of regexps in `editorconfig-exclude-regexps'."
   (interactive)
   (when (and major-mode buffer-file-name)
-    (editorconfig-apply)))
+    (with-suppressed-warnings ((obsolete editorconfig-apply))
+      (editorconfig-apply))))
 
 
 ;;;###autoload

lisp/editorconfig.el

@@ -251,9 +251,7 @@ Otherwise, use `delete-trailing-whitespace'."
   :type 'function)
 
 (defvar-local editorconfig-properties-hash nil
-  "Hash object of EditorConfig properties that was enabled for current buffer.
+  "Hash object of EditorConfig properties that was enabled for current buffer.")
-Set by `editorconfig-apply' and nil if that is not invoked in
-current buffer yet.")
 (put 'editorconfig-properties-hash 'permanent-local t)
 
 (defvar editorconfig-lisp-use-default-indent nil
@@ -527,9 +525,7 @@ This function will revert buffer when the coding-system has been changed."
 
 (defun editorconfig-call-get-properties-function (filename)
   "Call `editorconfig-core-get-properties-hash' with FILENAME and return result.
-
+This function also removes `unset' properties."
-This function also removes `unset' properties and calls
-`editorconfig-hack-properties-functions'."
   (if (stringp filename)
       (setq filename (expand-file-name filename))
     (editorconfig-error "Invalid argument: %S" filename))
@@ -541,6 +537,12 @@ This function also removes `unset' properties and calls
                            err)))
     (cl-loop for k being the hash-keys of props using (hash-values v)
              when (equal v "unset") do (remhash k props))
+    ;; E.g. for `editorconfig-display-current-properties'.
+    ;; FIXME: Use it for memoization as well to avoid the duplicate
+    ;; calls to `editorconfig-core-get-properties-hash' (one for
+    ;; `editorconfig--get-coding-system' and one for
+    ;; `editorconfig--get-dir-local-variables')?
+    (setq editorconfig-properties-hash props)
     props))
 
 (defvar editorconfig-get-local-variables-functions