Add support for math symbols

[Visgean]

The extension is brilliant way of entering symbols! One thing that I in general hate to type are math symbols. Using this extension to type stuff like lambda, sums, limits, would be so much simpler.

This should be relatively straight-forward to do. It should be enough to add them to https://github.com/maoschanz/emoji-selector-for-gnome/blob/master/emojisKeywords.js and https://github.com/maoschanz/emoji-selector-for-gnome/blob/master/emojisCharacters.js

What I don't understand is why is there two files and not just one with mapping of emoji to description?

I will try to make a PR.

I have found various websites with data-sets on this:

• https://www.compart.com/en/unicode/category/Sm
• https://www.fileformat.info/info/unicode/category/Sm/list.htm
• http://jrgraphix.net/r/Unicode/2200-22FF
• http://xahlee.info/comp/unicode_math_operators.html
• https://en.wikipedia.org/wiki/Mathematical_operators_and_symbols_in_Unicode

[m93a]

You'd usually want to use ComposeKey for math symbols. It's a lot faster. If you didn't want to make your own sequences for everything, you can peek into my custom sequences for greek letters, math symbols and sub- & superscripts.

The difference between math symbols and emojis is that math symbols have a precise rigorous meaning that can be categorised using as few as two ASCII symbols. Emojis on the other hand are intuitive and visual and you often choose the appropriate one when you see it, not sooner. That's why I think this extension is ideal for emojis but not very good for math symbols.