Automatically add a space before the emoji if the user is typing Chinese and uses emoji picker

[sam (Sam Saffron)]

We half fixed this with:

https://github.com/discourse/discourse/commit/d2a7a4916abecea389c99ae84de3bd40517b00d9

But what we need to do is match the implementation here:

https://github.com/discourse/discourse/blob/master/app/assets/javascripts/pretty-text/engines/discourse-markdown/emoji.js.es6#L154-L156

Which is checking for isSpace or isPunctChar.