Fix explainxkcd extraction on 2408

Author: zjn0505

fastlane/metadata/android/en-US/changelogs/75.txt

@@ -1,3 +1,4 @@
 - Fix compatibility with Android 12
+- Fix explainxkcd extraction on xkcd#2408
 
 Full release note on https://is.gd/xkcd_app

fastlane/metadata/android/zh-CN/changelogs/75.txt

@@ -1,3 +1,4 @@
 - 修复与 Android 12 的兼容性
+- 修复 #2408 的 explainxkcd 提取
 
 查看完整更新日志 https://is.gd/xkcd_app

xkcd/src/main/java/xyz/jienan/xkcd/model/util/XkcdExplainUtil.kt

@@ -15,7 +15,8 @@ object XkcdExplainUtil {
         val doc = Jsoup.parse(responseBody.string())
         doc.setBaseUri(url)
 
-        val h2Explain = doc.selectFirst("h2:has(span#Explanation)")
+        // https://explainxkcd.com/wiki/index.php/2408:_Egg_Strategies doesn't have Explanation span, good luck
+        val h2Explain = doc.selectFirst("h2:has(span#Explanation)") ?: doc.selectFirst("h2")
         val nextH2Element = h2Explain.nextElementSiblings().select("h2").first()
 
         val h2ExplainElementIndex = h2Explain.parent().childNodes().indexOf(h2Explain)