Fix digit/keycap unicode code points

Emoji digits and # are normal ASCII digits followed by COMBINING ENCLOSING KEYCAP (0x20e3). (Source: http://www.unicode.org/~scherer/emoji4unicode/20091221/emojidata.html)

```javascript
"0⃣".length
// => 2
"0⃣".split("")
// => ["0", "⃣"]
```