Support for the IPA Extensions block on Unicode

[inferno986return]

I am writing a book on Shavian, an alternative alphabet for the English language. The letter table which takes inspiration from https://www.shavian.info/alphabet/ uses IPA letters to help make pronunciation clear. There does look to be some support so it's just a matter of adding the missing glyphs.

I would also like to request support for the Shavian block in Unicode, but that would be a bonus.