; Improve documentation of last changeset (bug#69305)

* etc/NEWS (Example):
* doc/lispref/modes.texi (Tabulated List Mode): Improve
documentation of 'Buffer-menu-group-by' and
'tabulated-list-groups'.

* lisp/buff-menu.el (Buffer-menu-group-by): Doc fix.

doc/lispref/modes.texi

@@ -1248,7 +1248,7 @@ above form when called with no arguments.
 
 @defvar tabulated-list-groups
 This buffer-local variable specifies the groups of entries displayed in
-the Tabulated List buffer.  Its value should be either a list, or a
+the Tabulated List buffer.  Its value should be either a list or a
 function.
 
 If the value is a list, each list element corresponds to one group, and
@@ -1271,6 +1271,7 @@ from @code{tabulated-list-entries}.  For example:
 @end group
 @end smallexample
 
+@noindent
 where you can define @code{Buffer-menu-group-by-mode} like this:
 
 @smallexample

etc/NEWS

@@ -1358,8 +1358,8 @@ chat buffers use by default.
 
 ---
 *** New user option 'Buffer-menu-group-by'.
-It splits buffers by groups that are displayed with headings
-in Outline minor mode.
+It controls how buffers are divided into groups that are displayed with
+headings using Outline minor mode.
 
 ---
 *** New command 'Buffer-menu-toggle-internal'.
@@ -2077,7 +2077,7 @@ treesitter grammar.
 
 +++
 ** New buffer-local variable 'tabulated-list-groups'.
-It prints and sorts the groups of entries separately.
+It controls display and separate sorting of groups of entries.
 
 
 * Changes in Emacs 30.1 on Non-Free Operating Systems

lisp/buff-menu.el

@@ -96,15 +96,16 @@ as it is by default."
   :version "22.1")
 
 (defcustom Buffer-menu-group-by nil
-  "If non-nil, buffers are grouped by function.
-This function takes one argument: a list of entries in the same format
-as in `tabulated-list-entries', and should return a list in the format
-suitable for `tabulated-list-groups'.  Also when this variable is non-nil,
-then `outline-minor-mode' is enabled in the Buffer Menu.  Then with the
-default value of `outline-regexp' you can use Outline minor mode commands
-to show/hide groups of buffers.
+  "If non-nil, a function to call to divide buffer-menu buffers into groups.
+This function is called with one argument: a list of entries in the same
+format as in `tabulated-list-entries', and should return a list in the
+format suitable for `tabulated-list-groups'.  Also, when this variable
+is non-nil, `outline-minor-mode' is enabled in the Buffer Menu and you
+can use Outline minor mode commands to show/hide groups of buffers,
+according to the value of `outline-regexp'.
 The default options can group by a mode, and by a root directory of
-a project or just `default-directory'."
+a project or just `default-directory'.
+If this is nil, buffers are not divided into groups."
   :type '(choice (const :tag "No grouping" nil)
                  (function-item :tag "Group by mode"
                                 Buffer-menu-group-by-mode)