org-insert-heading: Fix when folded text is kept right at the new heading

* lisp/org.el (org-insert-heading): Do not slurp blank lines after
previous heading into the contents of the newly added one.  These
blank lines might be folded and we end up with point before folded
spaces * <point>...
* testing/lisp/test-org.el (test-org/insert-heading): Add test.
(test-org/insert-todo-heading-respect-content): Do not expect trailing
newline after the newly added heading.  The test did not intentionally
test this particular behavior (other tests do not expect trailing
newlines to be _always_ added).

Reported-by: Max Nikulin <manikulin@gmail.com>
Link: https://orgmode.org/list/ubpcoi$f7n$1@ciao.gmane.io

lisp/org.el

@@ -6323,7 +6323,10 @@ unconditionally."
        (if (not level) (outline-next-heading) ;before first headline
 	 (org-back-to-heading invisible-ok)
 	 (when (equal arg '(16)) (org-up-heading-safe))
-	 (org-end-of-subtree)))
+	 (org-end-of-subtree invisible-ok 'to-heading)))
+      ;; At `point-max', if the file does not have ending newline,
+      ;; create one, so that we are not appending stars at non-empty
+      ;; line.
       (unless (bolp) (insert "\n"))
       (when (and blank? (save-excursion
                           (backward-char)

testing/lisp/test-org.el

@@ -1965,7 +1965,21 @@ CLOCK: [2022-09-17 sam. 11:00]--[2022-09-17 sam. 11:46] =>  0:46"
 	  (org-test-with-temp-text "* H1\n\n* H<point>"
 	    (let ((org-blank-before-new-entry '((heading . t))))
 	      (org-insert-heading '(4))
-	      (buffer-string))))))
+	      (buffer-string)))))
+  ;; Do not include potentially folded empty lines.
+  (org-test-with-temp-text "
+<point>* Sec1
+** SubSec1
+
+text
+
+** SubSec2
+
+text
+"
+    (org-content)
+    (org-insert-heading '(4))
+    (should-not (org-fold-folded-p))))
 
 (ert-deftest test-org/insert-todo-heading-respect-content ()
   "Test `org-insert-todo-heading-respect-content' specifications."
@@ -1992,7 +2006,7 @@ CLOCK: [2022-09-17 sam. 11:00]--[2022-09-17 sam. 11:46] =>  0:46"
   ;; Use the same TODO keyword as current heading.
   (should
    (equal
-    "* TODO \n"
+    "* TODO "
     (org-test-with-temp-text "* TODO\n** WAITING\n"
       (org-insert-todo-heading-respect-content)
       (buffer-substring-no-properties (line-beginning-position) (point-max))))))