(use-dialog-box): Doc fix.

src/fns.c

@@ -5464,7 +5464,7 @@ Used by `featurep' and `require', and altered by `provide'.  */);
 
   DEFVAR_BOOL ("use-dialog-box", &use_dialog_box,
     doc: /* *Non-nil means mouse commands use dialog boxes to ask questions.
-This applies to y-or-n and yes-or-no questions asked by commands
+This applies to `y-or-n-p' and `yes-or-no-p' questions asked by commands
 invoked by mouse clicks and mouse menu items.  */);
   use_dialog_box = 1;