Inject Xdi8 per Ayaka

Annotate Xdi8 for Chinese characters on web pages. It is a powerful tool for learning the Xdi8 language.

Source of pronunciation data is Xdi8Translator: https://github.com/edward-martyr/Xdi8Translator

This add-on is open-sourced on GitHub: https://github.com/ayaka14732/inject-xdi8