Deep linking instruction may need an update

I'm trying to implement deep linking in my app but there are some inconsistencies between React Navigation's doc, React Native's and Android's which makes me feel confusing. For example, in https://reactnavigation.org/docs/en/deep-linking.html#android-1 it's talking about "Set launchMode of MainActivity to singleTask" with a link to the respective Android doc page, however there's no mentioning about this over there and the XML code snippet looks quite different; same is also true for the iOS section, the snippet given in https://reactnavigation.org/docs/en/deep-linking.html#ios-1 was outdated according to https://facebook.github.io/react-native/docs/linking

Someone in the know may wanna look into this and update the docs.

比較 React Navigation 的深度連結頁面與連結的 React Native、Android 和 iOS 文件，重點關注 issue 中提到的 launchMode 和平台程式碼片段。更新說明，使其符合目前的平台指引，然後驗證深度連結文件在各個章節之間保持一致。