优化

app/src/main/java/io/legado/app/constant/PreferKey.kt

@@ -93,7 +93,7 @@ object PreferKey {
     const val brightness = "brightness"
     const val nightBrightness = "nightBrightness"
     const val expandTextMenu = "expandTextMenu"
-    const val doublePageHorizontal = "doublePageHorizontal"
+    const val doublePageHorizontal = "doubleHorizontalPage"
     const val readUrlOpenInBrowser = "readUrlInBrowser"
     const val defaultBookTreeUri = "defaultBookTreeUri"
     const val checkSource = "checkSource"