Fixed a small issue thanks to contributor yjugl

- Missing null check causes JavaScript errors during navigation

Improved the Cantonese dictionary entries, thanks to @Michael Nock for your contribution.

Fixed a bug which prevented certain characters hot having all their readings shown.

I want to thank https://github.com/pcdi for pointing it out. https://github.com/JorisKok/chinese-firefox-quantum/issues/5

One feature added:
- Added a feature to start PeraPera by a customizable hotkey. The default key is Shift + P, but this can be changed anytime you want by going to the addon settings.

One bug fixed:
- Color coding for Cantonese now works with the jyutping

Fixed the tone marks for Cantonese users.

Small update regarding the html tags contributed by a user via Github.

Danke schön Philipp!

Added Cantonese support via the options page ( settings -> extensions -> preferences -> change mandarin to Cantonese).

Fixed the highlighting.