special-mode doc string clarification

* lisp/simple.el (special-mode): Make the doc string explain what
special modes are for (bug#37787).

diff --git a/lisp/simple.el b/lisp/simple.el
index cd674c36e7bc7079f4fc421a24bb4892b16736f4..338f3e3fd89faaf8c9f0d49b658ce6f124800bf4 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -474,7 +474,10 @@ Other major modes are defined by comparison with this one."
 
 (put 'special-mode 'mode-class 'special)
 (define-derived-mode special-mode nil "Special"
-  "Parent major mode from which special major modes should inherit."
+  "Parent major mode from which special major modes should inherit.
+
+A special major mode is intended to view specially formatted data
+rather than files.  These modes usually use read-only buffers."
   (setq buffer-read-only t))
 
 ;; Making and deleting lines.