Allow automatically marking the book as read on end of doc (#6256)

Keep showing the "mark as" option/button, though, because that one is a
toggle, it doesn't enforce the "read" status.

frontend/apps/reader/modules/readerstatus.lua

@@ -54,6 +54,12 @@ function ReaderStatus:onEndOfBook()
     if G_reader_settings:readSetting("collate") == "access" then
         collate = false
     end
+
+    -- Should we start by marking the book as read?
+    if G_reader_settings:isTrue("end_document_auto_mark") then
+        self:onMarkBook(true)
+    end
+
     if settings == "pop-up" or settings == nil then
         local buttons = {
             {

frontend/ui/elements/common_settings_menu_table.lua

@@ -465,6 +465,16 @@ common_settings.document = {
         {
             text = _("End of document action"),
             sub_item_table = {
+                {
+                    text = _("Always mark as read"),
+                    checked_func = function()
+                        return G_reader_settings:isTrue("end_document_auto_mark")
+                    end,
+                    callback = function()
+                        G_reader_settings:flipNilOrFalse("end_document_auto_mark")
+                    end,
+                    separator = true,
+                },
                 {
                     text = _("Ask with pop-up dialog"),
                     checked_func = function()
@@ -562,7 +572,7 @@ common_settings.document = {
                         return G_reader_settings:isTrue("highlight_action_on_single_word")
                     end,
                     callback = function()
-                        G_reader_settings:flipNilOrFalse("highlight_action_on_single_word", nil)
+                        G_reader_settings:flipNilOrFalse("highlight_action_on_single_word")
                     end,
                     separator = true,
                 },