(defcustom): Improve doc of `:group`

* lisp/custom.el (defcustom): Mention the use of a default group and
the fact that `:group` can be repeated.

(cherry picked from commit 4aa53f293455e690a9aa07eac13011020b887e0e)

diff --git a/lisp/custom.el b/lisp/custom.el
index 9f260f8ef4af27cbff0abb6cefd7104f1895c5be..f07ac716f642e7eb8b772568f7aa8868a6694196 100644 (file)
--- a/lisp/custom.el
+++ b/lisp/custom.el
@@ -306,7 +306,8 @@ The following keywords are meaningful:
 The following common keywords are also meaningful.
 
 :group  VALUE should be a customization group.
-        Add SYMBOL (or FACE with `defface') to that group.
+        Add SYMBOL (or FACE with `defface') to that group instead of
+        the default group.  Can be repeated.
 :link LINK-DATA
         Include an external link after the documentation string for this
         item.  This is a sentence containing an active field which