kourendlibrary: add config to hide dark manuscripts

runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/KourendLibraryConfig.java

@@ -63,6 +63,16 @@ public interface KourendLibraryConfig extends Config
 		return false;
 	}
 
+	@ConfigItem(
+		keyName = "hideDarkManuscript",
+		name = "Hide Dark Manuscript",
+		description = "Whether to hide Dark Manuscripts"
+	)
+	default boolean hideDarkManuscript()
+	{
+		return false;
+	}
+
 	@ConfigItem(
 		keyName = "showTutorialOverlay",
 		name = "Show tutorial overlay",

runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/KourendLibraryOverlay.java

@@ -127,7 +127,8 @@ class KourendLibraryOverlay extends Overlay
 					bookIsKnown = true;
 				}
 
-				if (book == Book.VARLAMORE_ENVOY && config.hideVarlamoreEnvoy())
+				if ((book == Book.VARLAMORE_ENVOY && config.hideVarlamoreEnvoy())
+					|| (book != null && book.isDarkManuscript() && config.hideDarkManuscript()))
 				{
 					continue;
 				}