master 3af2cee: Improve the docs of a recent change in mb-depth.el

[Eli Zaretskii]

branch: master
commit 3af2cee64b86e4ce59adb8e8720d92db35039cbc
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Improve the docs of a recent change in mb-depth.el
    
    * lisp/mb-depth.el (minibuffer-depth-indicator-function): Improve
    the wording of the doc string and of the label used for the
    default value.  (Bug#47252)
---
 lisp/mb-depth.el | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lisp/mb-depth.el b/lisp/mb-depth.el
index 3cba6a4..88003af 100644
--- a/lisp/mb-depth.el
+++ b/lisp/mb-depth.el
@@ -31,11 +31,14 @@
 ;;; Code:
 
 (defcustom minibuffer-depth-indicator-function nil
-  "If non-nil, function to set up the minibuffer depth indicator.
-It is called with one argument, the minibuffer depth,
-and must return a string."
+  "If non-nil, a function to produce the minibuffer depth indicator.
+The function will be called with one argument, the minibuffer depth,
+and must return a string to display as indication of the minibuffer
+depth.
+If nil, display the depth as a number inside brackets, [NN], with
+the `minibuffer-depth-indicator' face."
   :version "28.1"
-  :type '(choice (const :tag "Default" nil)
+  :type '(choice (const :tag "Default indicator display, [NN]" nil)
                  (function))
   :group 'minibuffer)