[BatCave] Small fix for getDetails (#1994)

src/main/kotlin/org/koitharu/kotatsu/parsers/site/en/BatCave.kt

@@ -106,9 +106,16 @@ internal class BatCave(context: MangaLoaderContext) :
 		val dateFormat = SimpleDateFormat("dd.MM.yyyy", Locale.US)
 
 		val scriptData = doc.selectFirst("script:containsData(__DATA__)")?.data()
-			?.substringAfter("window.__DATA__ = ")
-			?.substringBefore(";")
-			?: doc.parseFailed("Script data not found")
+			?.let { data ->
+				val jsonStart = data.indexOf("window.__DATA__ = ") + "window.__DATA__ = ".length
+				val jsonEnd = data.indexOf("};", startIndex = jsonStart)
+				if (jsonEnd != -1) {
+					// substring, include "}" symbol
+					data.substring(jsonStart, jsonEnd + 1)
+				} else {
+					null
+				}
+			} ?: doc.parseFailed("Script data not found")
 
 		val jsonData = JSONObject(scriptData)
 		val newsId = jsonData.getLong("news_id")