Better Wiktionary per Sin Jeong-hun

It currently includes the following features.

1. Context menu for word selection. Unlike other existing Wiktionary extensions, my extension reuses the tab, so if you look up multiple times, the browser will not be flooded with Wiktionary tabs.
2. Adds language switch icons next to the entry title. The entries can be customised in the settings page that can be opened by clicking the extension icon in the tool bar. This was necessary for me for learning French, because sometimes the English version for a French word entry did not have as detailed explanation as the French version. I need to switch between English and French version, and the stock way ("Languages" at the middle of the left bar) was not convenient.
3. Adds a button to toggle links. This is to make it easy to copy plain text.

More features will be added later...

Licence(s) for third-party resources

This extension contains the country flag icons from https://github.com/lipis/flag-icons. The icons are released under the MIT licence.