Fix documentation of :predicate in 'define-globalized-minor-mode'

* doc/lispref/modes.texi (Defining Minor Modes):
* lisp/emacs-lisp/easy-mmode.el (define-globalized-minor-mode):
Document that :predicate creates a customizable user option.
(Bug#64048)

2 files changed, 13 insertions, 7 deletions

diff --git a/doc/lispref/modes.texi b/doc/lispref/modes.texi
index 3eb61b4d565..4a54d6ec290 100644
--- a/doc/lispref/modes.texi
+++ b/doc/lispref/modes.texi
@@ -1888,11 +1888,14 @@ user option called the same as the global mode variable, but with
 @code{-modes} instead of @code{-mode} at the end, i.e.@:
 @code{@var{global-mode}s}.  This variable will be used in a predicate
 function that determines whether the minor mode should be activated in
-a particular major mode.  Valid values of @code{:predicate} include
-@code{t} (use in all major modes), @code{nil} (don't use in any major
-modes), or a list of mode names, optionally preceded with @code{not}
-(as in @w{@code{(not @var{mode-name} @dots{})}}).  These elements can
-be mixed, as shown in the following examples.
+a particular major mode, and users can customize the value of the
+variable to control the modes in which the minor mode will be switched
+on.  Valid values of @code{:predicate} (and thus valid values of the
+user option it creates) include @code{t} (use in all major modes),
+@code{nil} (don't use in any major modes), or a list of mode names,
+optionally preceded with @code{not} (as in @w{@code{(not
+@var{mode-name} @dots{})}}).  These elements can be mixed, as shown in
+the following examples.
 
 @example
 (c-mode (not mail-mode message-mode) text-mode)
diff --git a/lisp/emacs-lisp/easy-mmode.el b/lisp/emacs-lisp/easy-mmode.el
index 22ea12f0960..98c211325ab 100644
--- a/lisp/emacs-lisp/easy-mmode.el
+++ b/lisp/emacs-lisp/easy-mmode.el
@@ -450,14 +450,17 @@ TURN-ON is a function that will be called with no args in every buffer
 and that should try to turn MODE on if applicable for that buffer.
 
 Each of KEY VALUE is a pair of CL-style keyword arguments.
-The :predicate argument specifies in which major modes should the
+The :predicate key specifies in which major modes should the
 globalized minor mode be switched on.  The value should be t (meaning
 switch on the minor mode in all major modes), nil (meaning don't
 switch on in any major mode), a list of modes (meaning switch on only
 in those modes and their descendants), or a list (not MODES...),
 meaning switch on in any major mode except MODES.  The value can also
 mix all of these forms, see the info node `Defining Minor Modes' for
-details.
+details.  The :predicate key causes the macro to create a user option
+named the same as MODE, but ending with \"-modes\" instead of \"-mode\".
+That user option can then be used to customize in which modes this
+globalized minor mode will be switched on.
 As the minor mode defined by this function is always global, any
 :global keyword is ignored.
 Other keywords have the same meaning as in `define-minor-mode',