Explain in the tab-always-indent doc how to make TAB insert a TAB

* lisp/indent.el (tab-always-indent): Mention how to make TAB
insert a TAB character always (bug#37183).

diff --git a/lisp/indent.el b/lisp/indent.el
index 0a0dd99ce0813f1ffa6f4c303f5d1c7c860ff14f..9f32cedfa4a0203ba6bf1ff54ab19866d011a475 100644 (file)
--- a/lisp/indent.el
+++ b/lisp/indent.el
@@ -53,7 +53,16 @@ If `complete', TAB first tries to indent the current line, and if the line
 was already indented, then try to complete the thing at point.
 
 Some programming language modes have their own variable to control this,
-e.g., `c-tab-always-indent', and do not respect this variable."
+e.g., `c-tab-always-indent', and do not respect this variable.
+
+If you want the TAB key to always insert a literal TAB character,
+this can't be controlled by setting this variable.  Instead you
+could say something like:
+
+\(setq overriding-terminal-local-map
+      (let ((map (make-sparse-keymap)))
+        (define-key map [?\t] 'self-insert-command)
+        map))"
   :group 'indent
   :type '(choice
          (const :tag "Always indent" t)