org-fold: Prevent folding level 1 headlines

* lisp/org-fold.el (org-fold--reveal-outline-maybe): Never keep level
1 headlines inserted inside folded region hidden.  Such headlines can
often be added to end of buffer by capture.  This change prevents such
headlines to be hidden.

Reported in https://orgmode.org/list/CABUh-74vvn7i06T3zB=38_BFfBKS9J9H8NxGp_-eecoAPgygoQ@mail.gmail.com

lisp/org-fold.el

@@ -929,6 +929,11 @@ This function is intended to be used as :fragile property of
       (beginning-of-line)
       ;; Make sure that headline is not partially hidden
       (unless (org-fold-folded-p nil 'headline) (org-fold-region (max (point-min) (1- (point))) (line-end-position) nil 'headline))
+      ;; Never hide level 1 headlines
+      (save-excursion
+        (goto-char (line-end-position))
+        (when (re-search-forward (rx bol "* ") (cdr region) t)
+          (org-fold-region (match-beginning 0) (line-end-position) nil 'headline)))
       ;; Check the validity of headline
       (unless (let ((case-fold-search t))
 	        (looking-at (rx-to-string `(or (regex ,(org-item-re))