add gettext to readermenu

frontend/ui/reader/readermenu.lua

@@ -65,6 +65,18 @@ function ReaderMenu:setUpdateItemTable()
 			})
 		end
 	})
+
+	table.insert(self.tab_item_table.main, {
+		text = _("Languages"),
+		sub_item_table = {
+			{
+				text = "简体中文",
+				callback = function()
+					gettextChangeLang("zh_CN.UTF-8")
+				end,
+			},
+		}
+	})
 end
 
 function ReaderMenu:onShowMenu()